What terrible things has the Christia God done? Well, he is the all forgiving all knowing all loving God right? So instead of being kind and forgiving to his children, he decided to drown all but Noah's immediate family. Umm, can anyone say incest? That's one example...
Lets look at Moses.

He led his people (God's chosen ones) out of the tyranny of the Egyption rule. he followed God blindly and wholly. What did he do wrong? Once, only once, instead of accrediting the finding of water to God, he said "Do I have to find water for you myself?", he was forbidden to enter the promised land. Is that justice? One slip of the tongue, and the poor man never got to feel his whole life's work come into fruition. He died within sight of his goal, but was forbidden to enter it for this slight blasphamy.

lets look at Adam and Eve. God (who is omnipotent etc) obviously knew that the temptation of the tree would be too much for his children, especially with the Archangel Lucifer on the loose. Why would someone put the tree there as a temptation, if he did not want his children to fall? Adam and Eve were framed...

If they had not succumbed to the tree, they would have been submitted to other (worse and more devious) temptations. God has a cruel and unusual type of mind to come up with traps such as the tree of knowledge for his children.

What other proof do you need? Setting his children upon each other, pretending to be divine, judicious, and perfect.
All the examples that I have given are assuming that the Christian are right. If they are, then using their own arguments, their God is far, far from perfect.

This is just off the top of my head, but if I come back to it, I might think of a better worded rant about Jehova.