I answered Sometimes. For me the 'foundational belief' in question is usually along the lines: "Goal (x) is worth the effort of subgoal/process (y)." These moods usually last less than 6 months, and I have a hunch that they're hormonal in nature. I've yet to systematically gather data on the factors that seem most likely to be causing them, mostly because it doesn't seem worth the effort right now. Hah. Seriously, though, I have in fact been convinced that I need to work out a consistent utility function, but when I think about the work involved, I just... blah.