I know groups 'spam' a lot- posting up others work so their devation shows up twice on your watch and other things that may annoy some- but instead of leaving the group you can go to you deviants page and make it so you don't get updates. All you need to do is check or uncheck under the correct column to make devations/journals/polls/whatever go away so you don't have to see them- and it works for regular users too, not just groups.
I'm not saying your all stupid for not doing it if you haven't- I'm just reminding you its there and that you don't need to give yourself excuses to not join or anything. I have not received anything from anyone so don't worry. I just want everyone to know that if groups get too annoying then you can just put on some 'stealth' settings. You can still show off your love for fandom by being in a group but just not receive anything from them!
Besides it's not like anyone reads those things anyway, am I right?
However if you just don't feel the group's for you then by all means leave. No one's going to stop you and it's your decision and people should respect that. I know I do.
Again just a reminder to everyone about dealing with groups. I didn't mean to babble.
Happy Early Thanksgiving!