“One must imagine Sisyphus happy.” —Albert Camus, The Myth of Sisyphus
Yes yes I know Sisyphus is a metaphor for the pointlessness of life - but that doesn't mean you have to take it at face value.
In the original myth the rock rolls down alright, but it rolls down over our hero and then he has to go down and push it back up again knowing what will happen.
or perhaps that the work itself is the reward