One way to look at the what-the-hell pattern is as perfectionism. I set up a rule for myself, and if I fail to follow it even a little bit, then I might as well fail to follow it entirely: the only categories are "following the rule" and "not following the rule".

For instance, I may resolve to exercise every day. Skipping a day for any reason is a very strong predictor of also skipping the next day. "Exercising sometimes" feels, psychologically, like not following a rule about exercising, rather than like following a weaker rule or following it 80% of the time. (If I set up a rule to exercise 80% of the time, then I'll behave the same way with regard to that new rule, instead.)

There's probably research and information on dealing with perfectionism, but I don't know what it is.