Part of me says that this mentality is irrational, and that I should work to fix it. But maybe this is one of those times where the rational thing to do is identify how your irrational brain works, and then learn to work with it rather than against it.
I also see this as one of those things where “you shouldn’t stop yourself from doing the small good just because the big good wasn’t available”. Sure, it’d be better to just have a rational mentality, but if you can’t have that, then it’s better to just be rational about how your irrationality works. (And in the best case, we’ll find that it’s a stepping stone to a rational mentality.)
I also see this as one of those things where “you shouldn’t stop yourself from doing the small good just because the big good wasn’t available”. Sure, it’d be better to just have a rational mentality, but if you can’t have that, then it’s better to just be rational about how your irrationality works. (And in the best case, we’ll find that it’s a stepping stone to a rational mentality.)