I suppose you could say that I worship God for the rewards. Look at it this way: If there was no reward at all for worshiping Him, whether eternal life, material blessings, or spiritual blessings, how good of a god would God be? Of course we don't deserve anything, but He gives us grace because of His mercy. If He didn't care about me, why would I be compelled to care about Him? That's why deists don't worship God: They think He doesn't do anything.
Worship should be a total lifestyle, not just a time when we get together with the body of Christ and sing songs to God. It should be something that we do every minute of every day.
Firstly, we were created to know, love and worship God. God made us the way we are for that very purpose. Why else would He have given us a voice? He certainly wouldn't have done it just so He could listen to us fight and squabble. It was simply so that we could praise and worship Him. He desires us to worship Him and Him alone. He actively seeks true worshippers; people who will spend their lives worshipping Him and Him alone. In John 4:23 it says "But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him". Also, in Psalms 22:27 it says "All the ends of the world shall remember and turn unto the LORD: and all the kindreds of the nations shall worship before thee". This is repeated again in Psalms 66:4. It says "All the earth shall worship thee, and shall sing unto thee; they shall sing [to] thy name".
We were chosen by Him as a royal priesthood to praise and worship Him. I Peter 2:9 says "But ye [are] a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light".
Perhaps the most important reason why we worship is because we are commanded to do so. In I Chronicles 16:29 it says "Give unto the Lord the glory due his name; bring an offering, and come before him; worship the Lord in the beauty of Holiness." This is also repeated in Psalm 29:2, which says "Give unto the LORD the glory due unto his name; worship the LORD in the beauty of holiness" and Psalm 96:9, which says "O worship the LORD in the beauty of holiness: fear before him, all the earth".
We are required to give God the glory due His name, and this can only be done when we worship Him in Spirit and in truth. In Philippians 4:4 it says "Rejoice in the Lord alway: [and] again I say, Rejoice." In Psalms 99:9 it says "Exalt the LORD our God, and worship at his holy hill; for the LORD our God [is] holy". It is not an option! You are made to worship God and you are commanded to worship Him.