Atheism is simply the lack of belief in deities. It does not tell you how to live your life or treat other people. Of course, the same is also true of theism. Just having a belief in a god gives you no direction to take in life. Theists try to live their lives according to the religion that they follow.
Simple belief is just as lacking as simple disbelief.
It is where your belief, or lack thereof, leads you that is important. Not just the fact that you believe or disbelieve. Quite the opposite, in fact. People who do not accept the teachings of religion need something else to help them deal with life. If you are a theist you may well find that many of the following apply to yourself as well.