There are lots of answer to that question, but one of them is that I like to be in climates that cultivate a moral seriousness and reflectiveness, climates that routinely convict me and push me to be a better person.
Yes, there are lots of things I could do with those two hours on Sunday mornings. I could sleep in. I could mow the grass. I could read a book and drink a cup of coffee. I could take a walk. I could surf the Internet.
I could do all those things. But I find it a wonderful and profound use of my time to go to a place where we talk about deep, important things. I think it's a valuable investment to spend some time thinking about what sort of person I'm trying to become, where I'm slacking off and where I might do better.
Seriously, I've never been in a place that so routinely startles, interrupts, disturbs and shakes me to the foundations of my being as the church. It doesn't happen every week, but it happens with regularity. So why wouldn't I want to keep dipping into that milieu?
(Sometimes I jokingly call this my "Road Kill" theology of church. God doesn't show up every Sunday, but like a chicken running back and forth across a busy highway, eventually, if you keep showing up, the Holy Spirit will hit you like a truck.)
So yes, there's lots of things I could do on a Sunday morning. But all things being equal, I'd choose church every time.