@Op nice post.
I keep coming back for a mix of reasons. I like to try to give back what ever possible I can to do the website that really got me interested in internet memes. I enjoy the "contribution" aspect. Even though it is all voluntary, I can only do so much so trying is enough. (not everyone has to be SuperMan).
The community aspect is fine, even though things can get tiring, I feel it's ok for what it is. Also, in a community you can do certain things to irritate other users unintentionally, not every one is going to like you and can't make everyone happy. I just try to be funny in hopes that maybe just buy giving someone a laugh, they can find enjoyment, because I've had some really good laughs and experienced a lot of cool people and general knowledge of things that I probably never would have if I didn't try to be open minded and give people a chance to express themselves. For the people who are genuinely nice to me, I always appreciate it and really try to give back the same respect.
In a sense you have to keep coming back to be better at it, and lack of motivation is a struggle for me honestly. But if I helped anyone, it makes be feel better.
All I can think of right now.