Why are some people not Christian?

[PuppyFridayYall]

This has been something that has pestered me lately and I just don't think it makes sense inuitively to not be. Even more important and what I'm truly getting at is why do people not believe? I know there are satanics and other religions who do not believe in God but there are also people who do not have ANY FAITH whatsoever and my question is why?

1. It doesn't make psychological sense.
2. So the earth was made by whom then? ;- )
3. Why wouldn't you be? You have nothing to gain buy not following the word of God as he set it out.

I'm sure there are more people who can add to this in detail but this is what I could come up with on a moments notice.