Ultima 7: Having to manually feed your characters. Feeding your characters requires you to find the food item in your inventory (in a game with a bad inventory system), then use it on the character who is hungry. If you don't feed your characters, they will take starvation damage, so you can't just avoid the mechanic. It's really a shame that they decided to do this, particularly since Ultima 6 handled things better; you only need to eat when you rest, and the food is automatically taken from your inventory (not to mention Ultima 6's inventory, while not perfect, is better than Ultima 7's).
This is one of the many reasons I see Ultima 7 as being overrated and not really that good (the terrible battle system being another big one).
On the other hand, Dragon Warrior has a mundane task I actually don't mind: In order to progress, you need to get stronger. The primary means of doing so is to walk around in circles, killing the enemies that you encounter and getting experience points. If you are playing the original version of the game, this task takes hours; just take a look at a no-manipulation speedrun to see what I mean. (RNG manipulation is a thing in this game, and such runs are much shorter due to being able to skip all the time spend farming XP and Gold.) Note that the remakes of this game significantly increased the XP and GP yield of enemies, making the game much shorter as a result.
In Dragon Warrior 2, endgame leveling doesn't feel as mundane, as the enemies in the best place to get XP are not at all easy. There's enemies that can attack twice and use powerful magic, an enemy that can critically hit, an enemy that can cast Defeat (multi-target instant death), and even an enemy that can cast Sacrifice (if this happens, your entire party is dead). Combined with the fact that you revive in the shrine after a party wipe, losing only half your gold (at a point in the game where you don't need any), this actually makes this task quite fun. (If it weren't for the revive after party wipe, you could imagine how frustrating this would be (unless it appeared in a game that let you save after every battle).