yeah, can't is quite effective for limiting actions associated with it. like, i can't drink so much alcohol - because of health issues causing pain, caused by it.

i broke two of mine today, had two red bulls and 2 pints of cider. but that was all i got when i was out and getting more is easier to say "i can't" because it's a 7km bicycle ride and i deliberately stuffed the fridge full of good things, got some nice 100% chocolate buttons, 3 tubs of greek yogurt, 4 wheels of white cheese (two being goat) so i have easy access to good things now (yes, and i got loads of lamb chops, omg so good). these all make my health better so i can just sit here far from the shops and be happy with it and the "can't" works better because it is backed up by "why" and inconvenience.

there are some things that we do that we want to not do and deliberately obstructing these actions and casting them in a negative light helps wind back the habits that cause problems. in this case, it's actual pain, so "i can't keep doing this" and it's easier to not, which circles back around to "i'm not doing this anymore"