Then why does he deserve any credit or worship?
We only worship him because he is worthy to be worshiped. He gave you life and that alone gives him the right to ask for your devotion or love for him.
Rev 4:11 explains why believers worship God: "You are worthy, our Lord and God, to receive glory and honor and power, for you created all things, and by your will they were created and have their being."
God does not NEED worship. But he requires it. If you don't like it, then you don't have to worship him. No one is forcing you. But the "God is perfect and doesnt' need anything" argument from atheists/agnostics, just doesn't cut it.
What IS worship? Wikipedia defines it as an act of religious devotion usually directed to one or more deities. The word is derived from the Old English worthscipe, meaning worthiness or worth-ship -- to give, at its simplest, worth to something.
Basically it is giving to God our devotion because he is worthy, just as it is stated in Rev 4:11.