>At a high level human choices aren't rational which is sad, but we must accept it.

I can accept that but I have to ask: who would have the time to make a deep, rational analysis of the value for everything they buy? At some point I think the quick "discount heuristic" is the more rational choice because it saves time.

On the other hand, for big ticket items (cars and houses) I'd hope people would spend a lot more time making a rational choice.