The Daily Grind: He's simple, he's dumb, he's the guildmaster
Sometimes he's the head of the guild, sometimes just a member. He's friendly enough, minds the rules of the guild, and might even go above and beyond from time to time. He's never been anything but friendly to you. Whether you're waiting for a raid, or a special battlefield, or a city assault, he's there offering to come along if possible and cheering you on otherwise.
And as a result, it's a good thing he doesn't know how much you hate his guts.
We all know the guy (or girl) this is about. Whether by dint of horrendous stupidity regarding the game, or just a general attitude issue, you find yourself interacting with a guild member you can't stand. Sometimes even working extensively with them, depending on the game. When has this happened to you? What annoyed you about your fellow member so much? Perhaps most importantly, what did you ultimately do about it? From Star Trek Online to EverQuest, your guild is one of the most important parts of the game -- how do you tolerate an intolerable member?
