Who do you think is the most annoying character?
Annoying is a difficult quality for me to me to pinpoint. There are video game characters I despise. But I can't say they're annoying because they inspire a deep seated rage and aversion in me. An annoying character, in my mind, has to have enough good qualities (or at least tolerable qualities) for me not to wish them to the cornfield, but have persistent traits which get on my nerves.
Another problem with annoyance is in challenge. A really hard boss with earn my wrath, but again, if the boss is too hard, I'm more likely to give up on the game. An annoying obstacle has to be easy enough to surpass, but particularly bothersome in the method to surpass it. Because of this, I tend to be annoyed far more with game mechanics (such as in Final Fantasy Tactics and Ogre Battle 64) than characters themselves.
Finally, my memory fails me at times, and as a result, I forget about annoying characters. Of course, if I've forgotten about them, they're not all that annoying.
The most annoying character, in my mind is none other than Yuffie Kisaragi.
To be fair she has a lot working against her She's that archetypal, overconfident kid who joins the adventuring party. Her design in Final Fantasy VII is awful (in Kingdom Hearts, it's a lot less grating). But unlike most characters, she manages to be annoying in both a gameplay and story perspective.
I didn't like the Wutai sidequest. Heck, I didn't even like Wutai itself. Yet because I like playing games to completion, I did it.
In any other game, I would have just hated her. In a game full of characters who are awful either gameplay wise, or story wise, she is bumped up to annoyance given by the fact she is useful...when she isn't stealing your materia.