My fear is sometime I'll log in and they won't be there. Not that I got kicked for inactivity--we've got some active military in my guild so we're cautious on these things--but that some guild-destroying drama erupted while I was gone and I'm now guildless. (Note: not affiliated with that guild; it just came up in Google.) My guild is a fairly stable guild--the guild itself is three years old, so I think we're gonna make it.
What would you do if that happened to you? Me, I'd jump servers. My guild is the only bond I have with my server as I have several RL friends on another server. Thankfully, my guild rocks that much that leaving the guild and going to my friends' server has never been seriously considered.