So, if you weren't restrained by your belief in God you'd feel competely justified in doing whatever immoral behaviour entered your head. To quote you, "It doesn't matter at all" if God doesn't exist. Can you please notify your local police department of your lack of an innate moral sense, in case you ever get a crisis of faith. I sure hope that I don't live near you, I'd be really worried that something might shake your faith in God and then you might murder me if you wanted my possessions or my wife, as apparently your faith is the only thing stopping you from such acts.
If there is no God, then there is no morality.
Ever wonder why atheistic socialism had no problem murdering millions?