Why do we worship God? The standard answer is: because He tells us to. This answer is inadequate - it gives the impression of an insecure, neurotic Deity that constantly needs to be told how great He is. If He needs to be told, He can't be that great.
Why do we need to answer this question? Partly because the lack of an answer misleads those who don't worship Him, and partly because we need to understand or we will experience problems in our worship.
Why should we worship God? I can think of five good reasons.
Worship is what life is all about.
Perspective.
As we look on His face, we are transformed.