The present paper is an exploration of the economics of subjectivism and opportunity or alternative costs. Most contemporary economists pay lip service to these concepts, but when push comes to shove, all too often they jettison them. We shall illustrate this lapse from basic economics with a challenge that has been perplexing several modern economists: why do people always walk on staircases, but only sometimes on escalators. Landsburg (2002) misunderstood the reason people only sometimes walk on escalators, whereas they always walk on stairs. Garrison (2009) tackled the same problem, with somewhat different results. Both of them, however, are guilty of a failure to use what is perhaps the most fundamental concept in the economist’s toolkit – opportunity cost, known to an immense number of non-economists by the aphorism ‘There’s no such thing as a free lunch.’ This oversight resulted in his (their) failure to explain why people only sometimes walk on escalators, in contradistinction to the fact that they always walk on staircases.