alt Hacker NewsDon't. Motivation external to the self will always be ephemeral and fleeting, like a drug (hence the popularity of "motivational" content on YouTube). If you don't have a genuine desire to do the thing, don't do it. Not because you can't do it, but because you lack the internal drive and inspiration to do it (and that may just be right now, not permanently).
Yes, extrinsic vs intrinsic motivation. Sometimes, you MUST do a task (taxes, take a driving test, etc).
And, yes, the extent that tasks start from intrinsic motivation, you're ahead of the game. For me, this is making habits (personal example: eating less). Habit frees you (mostly) of the need for any sort of 'motivation' - it's just Habit.