I once heard someone say "Jesus is not my crutch. He is my stretcher!"
I could not hobble myself to heaven even if I wanted to. I need Him to carry me.
The "switch" which gets from from being a theist to being an atheist is at the point where you go from
"I can never be good enough, and need Jesus to get me to heaven"
to
"I am good enough, and if god doesn't recognize that, then he is an unjust god, and I don't want his heaven, anyway."
Basically, you take the external morality/ethics you were raised with, and internalize it to build your own sens of what is right and just. Often, the internal one is much more just than what you have been taught (it was the internal morality that defied religious teachings to fight for things like women's rights, freeing slaves, letting people ask taboo questions, etc.)
I guess it comes down to humility. Accepting that I am not OK on my own is a big part of it. There is a common teaching nowadays that tells everyone, "The power is in you" or "Just believe in yourself." But if I am completely honest with myself I realize that I am a wretched sinner. I don't have the power in myself at all.
This here is the big, monstrous lie that churches have been coonvinciing people with for centuries, for the sole purpose of controling them. "
You *think* you are a good person, but trust us, you are not. You are a wretched, evil human being, and the only salvation is through us. You must listen to us, do what we tell you, and give us your money, since that is the only way you will not e an evil person." It's the ultimage brainwashing power-grab, and it took a lot for people to overcome it, accept that they are not evil, and start the renaissance that brought us out of the dark ages. I am sorry to hear that you are still a victim of this lie, and don't even realize it for what is, which is some PEOPLE'S way of forcing their control over you.
I have evil thoughts and desires and without God's help I would give into temptations that only His Spirit helps me withstand. Maybe I am a just "bigger" sinner than others and realize this? I often think the most dangerous place to be is to be a good and decent person because those are the people that never realize that they even have any problem to begin with.
If you are at heart an evil person, and are dependent on god to keep you in line, then why would you deserve heaven? If a child is really boysterous, loud, disruptive, destructive, and is downright evil, and the only reason the child behaves is because her parents are forcing her to behave, is she really a good child? I don't think so. I would not reward that child for being forced to follow orders, since I know that she is, in reality, a bad person, and that the good face the child puts on is just a forced lie.