God died to make god happy?

I've heard it a million times, Jesus is god incarnate, and it was Jesus who died for our sins. well, i stopped and thought about.....so God sacrificed himself to himself to change a rule he made himself ? This omnipotent, omnipresent, omnibenevolent being just couldn't have just forgiven all those people, rather than have his "son" be born and then beaten, abused, and then murdered to forgive us for or sins? it's ridiculous.