I like the idea set out in the 'Preacher' comics:
God feeds on love and delights in knowing that no matter how much he visits people with plagues and atrocities people will always love him even when he has given us no real evidence he exists.
He made the universe because he was lonely and wants to have things that love him.
Making him a bit of a narcissist, really.
Edited by Larni, : Spelling