I voted for-
"Too many circular discussions - been there, done that."
"Because x, y, or z person is so set in their views there is no point."
"This is a great little community - that's why I'm here."
Reasons?
Well, it does get old discussing the same thing over and over again. And it also gets old because the usual debators are so set in their views that there isn't a point. It got to the point where I could predict pretty much exactly what the people were going to say next...
The forum goes through phases. The veterans stop debating, new people join the forum and start threads to debate and debate in other threads. Then those people get tired of it and leave, and more people come in to start more stuff up. I think we're in a typology depression right now, when the new people show up and ask questions is when the forum is booming with typology stuff. And when people start leaving is when it goes through a depression.
So I stick around because of the people here. I really like the community! I also stick around because of the enneagram. I haven't really found an enneagram forum that's much like this one. I also like being here because I like to debate.
I don't usually speak my mind on here, but I didn't vote that option because that isn't the main reason I don't participate much anymore (like the above ones are). But I don't usually speak my mind on here because when I do some idiot comes in to tell me how their opinion is better; or I sound like a dick (because I definitely can be with my views on people and things, so I normally just shut my mouth in most situations). Or I just get ignored, and the Ne dominant who's dominating the thread gets all of the attention over me and some of the others expressing their views.

Which I wouldn't be surprised if that happened to this post.