Opportunity Cost is a powerful concept. Time is precious. Assets are valuable. They are limited, and used in one way, they can not be used in another. To make good decisions, you can't just look at costs and benefits. You have to look beyond. Look at the world of opportunity, and what the thing doing the doing could be doing. But Opportunity Cost is a tough task master and favours things we already understand. Things that can be reduced to numbers. It is in a rush. Sometimes there is a cost to not pausing your calculation of opportunity cost.