We should go to church because it shows God we love him. That we're willing to take a little bit of our busy lives and pay him attention. There are only so many ways we can show that we appreciate, love, and respect him, and one of the best ways is to give him some of our time that he actually gave us in the first place.
If you told your grandmother that you've been too busy and haven't had time to call or stop by, but she knew you had been getting out doing fun things like going out to dinner, seeing a movie, going to a barbeque, etc., how would she feel? Would she feel loved? Would she feel like she matters? Of course not.
In my opinion, God is no different in this regard. If we rarely call him (prayer), and don't stop by and see him (church, where two or more are gathered to worship), why in the world would he believe us? The Bible whether the Old or New Testament, is a message of less talk and more action. I'm in no way saying that people must go to church to get to heaven. I'm just saying that if you care about outwardly demonstration some love to him, you might want to think all of this post over.
Just some things to think about.