What type is it that what they do has to feel right? They can't just continually do something if they're not in the mood for it. It doesn't matter if it makes logical sense, or ethical sense, this person has to feel in the mood or else they will have trouble. They could keep going, but they don't because it feels wrong, and they strongly value feeling right about what they're doing. It's not necessarily a matter of ethics, but the personal feeling behind it. This type of person is usually very skilled at something and can accomplish the unthinkable (even more so than others) when their mood is just right. I sort of see the caricature of a melancholic and an idealist, but you think this is type related? (at least in specific cases or stages)