If you're being honest, which games just demanded too much from you skill-wise/patience-wise?

Here's a couple I can think of:

Revenge of the Titans - It has some sort of adaptive difficulty system, based on how much money you have. Incredibly fun game, but about 80% in it just became too hectic for me to handle.

Super Meat Boy - Well, I completed the base game with little problem, but then I tried to systematically work my way through the dark world versions of the levels. Gave up on this infernal level: https://www.youtube.com/watch?v=bTPT2kv6PXw
I actually did manage to beat the first part, but just couldn't get the timing right on the second part. Rather annoyingly so since it's easier than the first part and the third part seems like a cakewalk compared to the first two parts. I was just too worn out.

Mount Blade Warband - Perhaps not so much difficult than just frustrating. I managed to destroy two of the game's factions (Kerghits and Vaegirs), netting me the largest kingdom. However, the remaining Rhodoks had too big of a kingdom. Hence any lapse in the war effort against them on your part will mean that their final castles/towns will be defended by absolutely massive armies, armies that I would have a hard time matching. The big mistake I made was not too pursue enough positive relations with the world's lords, hence my kingdom, while larger than the Rhodoks, had far fewer vassals. Spending another month or two trying to wipe out the rest with this handicap is just too much.

M.A.X - Mechanized Assault and Exploration - Could never beat the first level. Should probably try again.

Dark Reign - Got to the 3rd level I think, but no further.

Getting over it - Screw this game! Never again...

Nethack - No shame in this I reckon.

Castlevania (NES)
Castlevania III (NES)
Metal Gear (NES)
Gauntlet (NES)
Rygar (NES)
Mega Man (NES)
Mega Man 2 (NES)
Shatter Hand (NES)
Batman (NES)
RoboCop (NES)
Dark Souls (Depraved no level challenge) (PC/PS3)
The Guardian Legend (NES)
Deadly Towers (NES)
Addams Family: Fester's Quest (NES)
Athena (NES)
Kid Icarus (NES)
Top Gun (NES)
After Burner (SMS)
After Burner II (SMD)
Contra (NES)
Ninja Gaiden (NES)
Ninja Gaiden 2 (NES)

There's a quick start list.

Bunker Punks - Procedural generation really rams it up the cornhole on the highest (Brutal) difficulty, to the point where I beat it on all other remaining difficulties and secured every achievement to be had on it, save the one for beating the game on that final difficulty. The sad thing is, I don't necessarily dislike the game even though I really don't like proc-gen elements (especially in FPS titles) but when I'm at the mercy of a pretty fish-brained algorithm that generates ultradookie layouts to run through while I'm trying not to take a single hit because at that difficulty even being armored to the hilt can rip a character apart like tissue paper then it's not a fun challenge, it's just a dick-rippingly bad time all around.

There are probably others but that's a recent one that springs to mind.

Aquaria - great game, but the final boss fights are just too much. Not necessarily on their own but because you need to do several of them in a row without checkpoints. Too much stress and tedious repetition.

Anodyne - liked it until jumping pad mechanics were introduced. They're just broken, and at some point they actually became game-breaking for me. A shame because I was close to the end with this one as well.

Albion - aka the game who probably made me a hoarder - nah, just kidding, but in this game I actually had to give up my playthrough shortly before the ending because I didn't have enough ammunition left to beat the final fights.

Knights of the Chalice - I don't enjoy the stretches where you get locked inside a dungeon and worn down by one challenging battle after another, fully aware that there will be an even more challenging boss battle at the end of it, but not knowing when or if you will get a chance to rest again. These dungeons are too big and hard and just not my idea of fun. I liked it better when you still had the option to retreat.

Vagrant Story - the bosses' damage immunities can drive you insane. Even after consulting guides and paying close attention to building up the various weapons' specialization, it still happened too often that my weapons dealt next to no damage to a boss. No fun. And at a certain point in the game, these boss battles abound. You can't walk three rooms without another one stepping in your way. A shame, because otherwise it's a pretty cool game.

Marlow Briggs and the Mask of Death - game was fun, but I have yet to beat the final boss. I don't have enough patience to go along with the patterns round after round only to chip away at this huge sponge's health bar bit by bit.

Mr Shifty - another game I almost completed but have no patience for the last level, because if you don't beat the final confrontation and postpone the next try, the next time you have to start the whole level from scratch, and that's boring. And even if you try again right away, you still have to repeat several minutes of arena style challenges with waves upon waves of enemies before you get aother shot at the boss again. And the gameplay is like Hotline Miami, meaning one wrong move, you're dead.

Star Wars: The Force Unleashed - controls are clunky but I managed to play through 98% of the game anyway, but the final boss battle is terrible. Wouldn't even be that difficult if it wasn't for the controls, the fight itself is unimaginative run-of-the-mill puzzle/phase combat.

Owlboy/Cave Story/Super Panda Adventures - I'm stuck on some boss battles halfway through.

Braid/Fez - could be nice enough games, but I find them too top-heavy and frustrating; the ratio of progress vs. obstacles is too much out of balance for me to enjoy them

Fahrenheit/Indigo Prophecy - fed up with all those silly and distracting QTEs

Well, of course there are more, but I haven't advanced far enough in those to even consider completing them. Beating games like Dark Souls or Super Meat Boy is not really on my bucket list. There are better things I can do with my time.

UU DD LR LR B A START

Monster Boy and Cursed Kingdom is game I abandoned after getting stuck, but I'm back on track
La Mulana 2 has some really devious bosses and after getting stuck on one, I'm back to getting stuck on Kujata, who's supposed to be nerfed.

The New Satan Sam pretty cool 2d game with lots of jumping and shooting and weapons. Did beat the game but the extra level called echo world had an invisible labyrint and i never got through it :(

Final Fantasy 8, definitely not leveled enough for the final area, when stripped of all skills for that first boss fight there was absolutely no way to win with just regular attacks, tried dozens of times, even plenty of luck on the RNG still got me nowhere, and I had no intention of returning through the gates to grind, so just watched the rest on YT.

Almost every RTS I tried to play, though I used cheats for some early on, probably only managed to finish Homeworld 2 and Kohan 2 normally. May be a chance I finished Warcraft 2 and the expansion normally too, but doubt it. StarCraft and expansion, Age of Empires 1 and 2, Warcraft 3, Empire Earth and expansion, nope. Age of Empires 2 completely crushed me right away, think I completed one scenario of one campaign. Not sure of AoE1 anymore, struggled with that for long so might have gotten far but really can't recall. In Brood War I got close to the end, 2-3 Zerg missions left, when I just couldn't advance anymore (can't remember the original anymore, whether I didn't try enough or finished with cheats or what). In WarCraft 3 I got to that last undead mission, no way I could last long enough, managed to lose with under a minute left, think under 30 sec once or twice, but not a chance for those final moments. And in Empire Earth I gave up quickly when it got to modern warfare, the campaigns in the World Wars in both original and expansion, that doesn't interest me, but I did try a bit, was thoroughly crushed several times, said screw that.

Battle for Wesnoth, completed a few campaigns, but when it got harder the turn limit crushed me. Stopped at a scenario where I just couldn't figure out how to even reach the goal in time, much less have enough forces there to win, and it was just a supposedly intermediate campaign I think.

Pretty sure I also didn't finish Black & White, seem to recall being under constant attack in I think the 4th scenario? Struggled for a while, but was an exercise in frustration.

Heroes of Might and Magic 2 and Heroes of Might and Magic 3, I wasn't really getting anywhere, the hero trains needed, the expendable heroes you were required to have, not something I'd use, so didn't work. Likely ended up farther in 2 due to sheer persistence, and some luck, but not sure anymore. In 3 I think I just finished one campaign, kept banging head against the others from that first batch and getting nowhere, so obviously further ones were never unlocked.

Supaplex, though I did get quite far, and I put an insane amount of time in that way back in the day, but there were levels I just couldn't get through and eventually had to stop.

And then there's Gothic 2 Gold, which I still hope to get back to and finish someday, but installing NotR makes it painfully hard and character development too frustrating.

Probably a fair few more, but this is what I have now.

Hehe about Nethack. Every now and then I do a run or three. Never reached the end.

Many games I intend to return to one day but may never do.

I once gave up on one playthrough of Mount & Blade due to my king (you can only be a vassal in the original game) scewing up the end game thoroughly by waking up late and taking the two towns still not part of our kingdom and leaving two castles which demanded siege towers, meaning huge problems besieging them with large armies due to moral problems, to me, then when I had slowly whittled away the enemy armies to a point where I could lay siege to the other castle with a chance at winning, my good liege makes peace... I must have cursed for a full five minutes and abandoned the game there and then.

I guess I gave up on the campaigns in Cossacks - European Wars and Cossacks - The Art of War. I got somewhere in them all and then stuck hard. I guess looking at some guides could help here. Same for Empire Earth.

Firestarter, hunting those artefacts drives me mad. A pity as the game is alright otherwise.

Err brain fart on my part. I had a whole response prepared thinking you were talking about Jedi Outcast :P After all you were talking about a horrible final boss fight, which Jedi Outcast and Jedi Academy are both guilty of. But then I realized that 'clunky controls' just doesn't make any sense if you're talking about those games :)

I've been meaning to check out Force Unleashed, but like you said, the controls appear clunky. I suppose in part it's because of the lock on mechanics necessitated by it having to be playable with a controller. It works for certain games like Batman and the like, but Jedi Outcast + Academy I think showed pretty clearly that the best lightsaber combat requires total freedom. Yup, this is an unfortunate thing in an otherwise excellent game. You need scores of expendable heroes to ferry troops around because you don't have the time to use your main hero to go and collect troops each week. It's the game's one major design flaw. If only troops could move around without a leader, or with the aid of some other unit like an explorer/tracker/marshall.
You could maybe still get away with not relying on this in the basegame, but you'd have no chance I think in the expansions.

I got pretty far with a crazy powerful ranger once. But then I stepped on a polymorph trap, turned into a rat, suffered a bout of teleportitis shortly after (ate a leprachan) and found myself facing off against an angry air elemental. Rats can't beat air elementals. Kind of facepalmed-quit right then and there and haven't had the courage to return since...

I haven't played Jedi Outcast yet, but I did play Academy earlier this year and I still remember that final boss. That's the one I beat without taking a single hit by running laps around the outer edge of the arena with the boss chasing me the entire time. As soon as my force lightning ability recharged I'd turn around and zap her and then back to running laps. Felt more like something from a comedy movie.

I quit Star wars: The Force Unleashed too. One of the worst games I've ever played. I'd like to set one thing straight about that game. If you read the GOG and Steam reviews you would get the impression that the game is a bad console port. I played the console version and the PC version and I can say that it's just a terrible game with equally bad controls no matter what. Just a bad attempt at making a Star Wars God of War game- right down to the shitty QTE's during boss fights.

I believe most games are beatable, they're just not fun enough to pour time into. The counter-argument to this would be [url=https://en.wikipedia.org/wiki/Flow_(psychology)][the flow state[/url], and that games you "can't beat" simply means "games you're too bad at to keep having fun until you beat it".

Games I enjoy but have a hard time seeing myself ever finish completely:

Super Meat Boy
Fuck this fucking piece of fuck would be the best way to describe how this game makes me feel while playing it. And yet I come back for more fucking shit. I need help.

Every true roguelike except Tales of Maj'Eyal
No shame in not being able to beat roguelikes, the only one I think is going to keep me motivated all the way through is Tales of Maj'Eyal. It might not be today, it might not be in 10 years, but one day I will finish it.

Contra 4 (Nintendo DS)
This might be one of the hardest games I've ever played. Pure torture, but the good kind. You know, consensual torture. Until it's not, then you turn it off.

Every bullet hell out there 1CC, the only true way to beat them (one credit clear)
How I've tried to achieve 1CC in all kinds of bullet hells, and how I've failed miserably. It's rewarding as all hell to strive for, but it feels unrealistic to actually achieve this goal.

Super Hexagon
Just thinking about this game makes me twitch nervously.

Same with running and not being troubled. Not sure of lightning though, maybe it was that life drain ability, upgraded to ranged?
They fixed that in 4, AND the fact that heroes were just cowards hiding behind their troops and running away if left alone, making them actual units, and being able to group more. Why I really liked that one... and fans of the previous ones didn't...

^This.