Who is the most annoying character in any book you've ever read?
Hm, there have been annoying characters in books I've read. Effie in The Sisterhood of the Traveling Pants series was annoying when she took the pants and when she was dating Brian. The aunts in James and the Giant Peach where just plain annoying. I'm looking through the books on my bookshelf and re-orientating myself with the annoying characters. Cokie Mason was annoying in the Baby-Sitters Club. Haymitch is pretty annoying as a drunk in the Hunger Games, not so much in Catching Fire, and I haven't seen enough of him yet in Mockingjay (I'm only 27 pages in). Snape fans are pretty annoying when it comes to Harry Potter, but they're not characters so they don't count. :p
The most annoying, though? That's a tough one. I know there's a character out there I've just wanted to slap. I'm trying to remember who it is. I'll come back if I remember.