Trying to build upon "it sucks that ..." seems to create a bunch of weird self sabotaging behaviours in my experience. Since I tried moving away from that I've found it easier to motivate myself to do things that aren't immediately rewarding. And perhaps more importantly, the journey there seems more enjoyable.
And I think it makes a lot of sense that using a carrot instead of a stick on yourself produces more consistent behaviour. You move towards a carrot and you flee from a stick. You can flee in most directions.
Changing the way you think about yourself takes a lot of time though. Impulses are deeply rooted.
But wanting the carrot and not wanting to get hit are both kinds of discontent. The donkey is dissatisfied at not having the carrot so it pulls the cart that would otherwise be still.