They are ignorant of God's existence or at least misinformed. They think that just because they cannot see something with their eyes it does not exist. They're pussies because they have never experienced or seen true evil and because of that they think life is a simple and easy and carefree existence void of evil and its opposite, good.
A person can gain knowledge of an after-life by experiencing the divine spirit of God that exists within themselves.
Atheists merely disbelieve in God, that doesn't mean they embrace evil. Atheism doesn't promote complacency and selfishness, what?
You might be interested to know that studies show atheists are more charitable (giving donations to charities) than religious people.
So...before you broad brush atheism, realize that your stereo type may be way off.