And even if you do everything right, there's never a guarantee that any given stressor will actually trigger a big enough set of adaptations to be a net positiv

And even if you do everything right, there's never a guarantee that any given stressor will actually trigger a big enough set of adaptations to be a net positive. Human psychology and physiology do not operate on some kind of magic quid-pro-quo system where ability or health exist to reward effort or discipline; sometimes stuff just doesn't work the way you want or expect and you have to deal with it any way you can.