I believe in myself
I would say that I hardly need a reason to not believe in God, it would be belief which needs an explanation. On the other hand, it may perhaps be caused by my inability to follow instructions.
Answering to a theist demand, is mostly based upon respecting their beliefs. Theists want atheists to help them pretend that their fictions/beliefs are fact.
Atheists can play this game out of respect, if you want to. Or you can demand that theists cough up there 'god' now, put up, or shut up. Since they can't, without playing head games with the language, we can walk away, engage with some funny attempt at 'why', or stand quietly in the shared ignorance. For most people 'silence' can be painful, you could offer them a cookie and call it done...
I cannot bear the thought of believing in an all-powerful, all-knowing universe creator who requires worship from us and displays anthropomorphic emotions.
That was another point, I just about forgot...;p)
Common bloody sense
Doesn't make any sense.
If he created us then who created him?
Like porn, "God" is an artificial concept so people can jerk themselves out while thinking about it.