Let's imagine this: you are God. You are in Your Heaven. And you look down and see all the little people that You created, that You give life to, that You ultimately control. And here they are trying to deny You, and ignore You and do their own little thing and deny that You exist. You've offered them a way of life, but they don't want it. 
So, I'd be up in my Heaven with my all-powerful self, like, fine! Do what you want! You look pretty retarded and I tried to help you, and you refused, and continue to refuse to let me, so see if I care. I'm gonna sit up here and laugh.
So it's a really good thing that I'm not God, because you'd all be doomed. Luckily, though, God isn't like me. God is love. He looks down from Heaven and instead of laughing at our foolishness, He refuses to let us go about life doing our own thing. He pulls us to Him. Not because He needs us, but because we need Him, and He loves us too much to let us go.