The other side of this is that I would expect my brain to NOTICE it's actual goals. If my goal is to make paperclips, I will think "I should do this because it makes paperclips", instead of "I should do this because it makes people happy". My brain doesn't have a generic "I should do this" emotion, as near as I can tell - it just has ways of signalling that an activity will accomplish my goals.

Iron deficiency feels like wanting ice. For clever, verbal reasons. Not being iron deficient doesn't feel like anything. My brain did not notice that it was trying to get iron - it didn't even notice it was trying to get ice, it made up reasons according to which ice was an instrumental value for some terminal goal or other.