Most people are abstractedly informed of opportunity cost, and its reckoning isn’t difficult. However, unless the costs are crystal-clear and overt people hesitate to weigh their imminent decisions. Yale professors note in their paper on “Opportunity Cost Neglect,”

This customer was frozen in indecision between a $1,000 Pioneer and a $700 Sony, and the salesman intervened, framing the choice as follows: ‘Well, think of it this way—would you rather have the Pioneer or the Sony and $300 worth of CDs?’ Remarkably, the decision that seemed so difficult just moments before was no longer even close—the Sony was at the cash register moments after the word CDs escaped the salesman’s mouth. A big pile of new CDs seemed far too steep a price to pay for the Pioneer’s slightly more attractive speakers.