I always find the best formula for rage games is the "troll" level-style game, where comedy is the central point. The game can have impossible-to-predict deaths (totally unavoidable the first time through), but after learning from mistakes you should have a clear way to progress, or even supply hints if too many deaths to the same troll occur. Checkpoints after every few minutes of trolls is also a good design, and sometimes even scaring the player with knocking them back to an earlier checkpoint is good for laughs (provided you don't actually send them back without a new path opening up) - in Mario Maker terms, this is the "CP1" gag.