When we worship God for who He is we are seeking the person of God. When we are worshiping God for what He is we are seeking the benefits of our association with God.
When we are able to worship without demanding a result we know it is for the love of God. This is when the glory of God shines brightest and the darkness flees from us. For we are made for His glory to enter into His rest in all that we are and all that we do.