There is a fantastic TED talk on this subject (well more than one, but one in particular) by Dan Gilbert that's one of my all-time favorites and which I refer back to from time to time for reminders about why it's important to estimate probability of outcomes and value of outcomes (really the only two factors that need be considered in decision-making):
https://www.ted.com/talks/dan_gilbert_researches_happiness?language=en#t-1940932