I have always viewed the mission of Wikipedia to be much bigger than just creating a killer website. We're doing that of course, and having a lot of fun doing it, but a big part of what motivates us is our larger mission to affect the world in a positive way
People do fun and interesting things because they're fun and interesting.
I just get up every day and do what seems like the most interesting, fun thing to do.
Ideally, our rules should be formed in such a fashion that an ordinary helpful kind thoughtful person doesn't really even need to know the rules. You just get to work, do something fun, and nobody hassles you as long as you are being thoughtful and kind.