One of the "common irritations" for folks on Second Life is the 25-group limit each Avatar is allowed. I'm at the state where I have to delete a group to be able to join a group already, and with my work I'm having to be a member of various groups to be able to do stuff for/with them. I guess this is REALLY bad for in-world DJs who need to join the group for each club they work for, which limits them to what they can do (or greatly inconveniences them to have to quit and re-join groups as gigs come up) ... and a group of DJs has started up a petition campaign to convince the Lindens to boost that up to at least 50 groups.