"Serve the Lord with gladness: come before his presence with singing.
Know ye that they Lord he is God: it is he that hath made us, and not we ourselves; we are his people, and the sheep of his pasture."
This reminds me of what we really owe to the Lord. It is so easy to slip into thinking about what we deserve or merit because of the work we've done, whatever that is. And we start lifting ourselves up... and yes, we should value ourselves and not throw our lives away as worthless... but compared to God, we're less than the dust that collects on the desk, and which we flick away with a cloth. It is because of him that we are as much as we are, and that we have the possibility of becoming greater. :) We owe him more than we can give... and so serving him with gladness is the way we pay back that which cannot be repaid. :) He did everything for us because he loves us, and all we can do is love him in return. :)