There is no agreed definition of God. Some say He is infinite, others say He is maximal, others say He’s just powerful. Some say God is the creator and don’t elaborate at all. But the one characteristic that many religious people do seem to agree on is that God is good. It is not that God is a good guy, but that by definition He is good. Therefore, if He’s not good, He’s not God. This is why atheists question the character in the Books: if I can make you question His goodness, you should also question His existence. This is (either accidentally or condescendingly) mistaken for being angry at God, often coupled with the snide question “how can you be mad at a God you don’t believe it?”
One commenter has asked whether I wish there was a good God and whether I’d want Him to save me. The question is a little confused; I don’t assume I need saving. In fact, it’s a self-fulfilling solution; religion offers both the problem of damnation and solution of salvation. It’s a neat little package. But without religion, you don’t have the issue of damnation so you don’t require the solution. I don’t want to be saved from drowning, because I’m not. (Although, the religious would have you believe I am.)
Questioning a ‘good God’ is an interesting one. I’m not convinced such a thing is easily described. God, according to many religious people, has a tendency to punish people for thought crime. That’s not good, and therefore needs to go. God, according to many religious people, could stop natural disasters but doesn’t. Therefore, either natural disasters or God’s ability to stop them needs to be stricken from the record. (If it is the former, then that would be good.) According to many religious people, God is watching us and judging us… I’m sure you can see where this is going: I can’t begin to imagine what a ‘good God’ would look like. I don’t know how many of His habits have to change and how many of those that do have to change are actually integral to His definition.
By the time I have reduced God back to such a time I would call Him “good”, I’m not sure what good He would be.