I dunno, I just do things because doing them is clearly a good deal for me. E.g. the amount of money the job will pay me at the end of the month is worth the amount of misery it causes. My "secret" is to have a very low cost of living, so basically every a monthly salary covers a year's worth of living expenses. And, every year at work is basically a decade shaved off of the total employment time (and a decade closer to early retirement).

With math like this, it's not that hard to motivate oneself. Which makes me think, if people are having a hard time motivating themselves do to things they ostensibly want to do, maybe doing them is not in their best interest (e.g. too risky, reward to far away, reward to small compared to equired effort, reward only monetary while other areas of live are badly neglected etc.). The friction in doing the thing may be your subconscious yelling at you: "wtf are you doing, stop, this isn't good for us".