Deuteronomy 12:28 NASB

Contrast this verse with verse 8 - The measurement of what is "...good and right" is in "...the sight of the Lord your God" - not in our own eyes (v8)

The reason is simple: We're too short-sighted to see beyond ourselves, so everything we attempt to do on our own will always be based around what we want or perceive to need; even in worship. That, ladies and gentlement, is a sad and dangerous truth. And that is why we need God in control of our lives.