Reading this thread is rather refreshing.
Messageboard communities can really bring out some personalities.
I think one of my biggest peeves is when a small group of members try to act like moderators. (Trust me--they ain't moderating material!

)
I also have one member (who is also in the above group) who likes to post in quite a few topics--and usually her posts are, "I agree."
I've decided, however, that she is a lonely young lady who probably doesn't have a lot of friends IRL. So if the board helps her to be part of something, I just ignore her and move on.
I do have one dicey situation where a member who left in a huff has come back. She's caused problems a couple of times. Like someone described, she has a lot of influence.
She was a moderator, but she got

when I tried to tell her that deleting posts that start a controversy--leaving the subsequent posts dangling--is NOT what we want to do.
So she left, and I removed her as moderator. I probably should've announced something, but I didn't. Sure enough, I soon had a "Where's ___" thread posted by another member.
I went in and posted and said that she decided to take a break from the board (her words). Then some of her buddies tried to bring issues into it--and all of a sudden, we had a board battle.
Ironically, she also created a board for herself--and recruited a small group of people from my site over to hers. She calls it, and I kid you not, the "no slam zone for _____". :rolleyes:
(She felt that she was being picked on ... she's the type who would zing someone with a subtle insult; for most, it'd go over their heads; for some, they called her on it ... and then she'd cry wolf--saying she was being picked on)
Her board must be pretty boring because she came back to mine a couple weeks ago and took over a thread.
With problem posters, I've taken the subtle route, and I've taken the blunt. I don't know if there is a right/wrong way--especially with those who have a screw-loose.
One other rambling thought--I've pretty much accepted the spelling, grammar, and punctuation errors that members make. What drives me crazy: ALL CAPS, too big of font (I have a hack installed that allows for font size to be altered), and broken UBB code (especially with the quotes).