Well, the biggest upside is that there are basically 4 of us running a top 100 internet site, so we each get a lot of responsibility. Also, anything we do affects the lives of literally millions of people, which is pretty cool.

And yes, the warm fuzzies I get when see the reddit community do something awesome are what keep me coming back day after day. Knowing that in some small way, I helped facilitate that awesomeness.