The fact that a doctor can treat the sick, save lives, continue to do good deeds and somehow ends up in the same place as genocidal maniacs like Hitler and Stalin, just because he doesn't believe in a mystical allmighty being for which little-to-no evidence exists, is morally abhorrent to me.
It's an absolutely repugnant stance that someone gets sent to eternal damnation for being an atheist, despite living a good life. If anything, the atheist should be given a higher reward. An atheist doesn't fear eternal punishment, nor hope for eternal reward; rather he does a good thing because he knows it's moral. Whereas most Christians do it just to get a free ticket "upstairs", as it were.