Origin of Morality

One of the criticisms atheists get for Christians is about morality. If there is no God (Yahweh, Allah, etc.), what is the basis for morality. Where does morality come from?
This is the wrong question.The more important question is, what is the purpose of morality. If the purpose of morality is to be subservient to an angry deity, to abandon one's loved ones as Jesus commanded (Matt. 19:29) or in some other way serves to undermine human dignity, then it matters not where it comes from. If instead the purpose of morality is to improve man, to make him a better person and maximize his well being, then the question become relevant.
If morality is a tool of man, to improve his life, then morality can be determined through reason. It is not perfect, but claiming a perfect origin for morality is to lose the ability to judge right and wrong. To that what God deems is right is, then when confronted with a moral dilemma, such as if to kill in God's name as commanded in the Bible, you may abandon your moral sense.
Recent history is littered with examples of Christian's killing each other, killing abortion doctors, Muslims killing non-believers, the list goes on and on. And rather then using the faculty for reason, they justice clearly immoral actions in God's name.
Whether or not you believe in any god, morality must be founded on something that all mankind can use, even if they choose not to.