The Curious Economics of Temptation

Undercover Economist ("The economic mysteries of daily life") Tim Harford writes in Slate on the Economics of Temptation.

One of the results of the recent research is that we have a sense of just how strong the pull of the now actually is. The answer is that anything on offer right now is worth half as much, again, as it would otherwise be; that also means that any immediate cost, such as the pain of going to the gym, is similarly inflated. (That is, you'd much rather go to the gym next week than today.) Of course, the costs will vary across people and across temptations, but that seems to be a consistent finding.