At the end of the year I was in a guild that had just started a second 10 man group. I was also working almost full time third shift as well which meant I had to actually drag my butt out of bed to get to the raid on time (read: 15 minutes before hand to make sure everythign was set addon/flask/food wise). Just call me one of those raiders who thinks of the other 9/24 people in the group and expects them to do the same.
So I was setting my alarm clock for my days off so I could paticpate in these raids. Let me tell you, when a raid interferes with your sleeping schedule you get uptight about others not taking the start time/sign up seriously. I became disenchanted with my raid group and the guild in general, no it wasnt the fault of any one person but the lack of any real consequence of not showing up was grating to say the least.
Around February the gm of the guild said some off hand but rather offending remark. She usually wouldn't do such a thing and as I now look back, I can see her anger over the raid group, at the time still faltering a bit, and the whole "pre cataclysm post most good stuff in expansion" time of the expansion. This time gets everyone into a huff. Well, I left the guild because the GM wasn't really responding the way I have come to know from her. Really wasn't anything important but I wasn't really in the mood to think about it at the time so I just pulled all my characters from the guild, pretty much without thinking of the long term consequences. So, my characters, just about every one, are guildless, and I only have myself to blame.
The bad part? I still love my old guild so much I don't want to even try another.