Waiting
Fairness also dictates that the length of a line should be commensurate with the value of the product or service for which we're waiting. The more valuable it is, the longer one is willing to wait for it. Hence the supermarket express line, a rare, socially sanctioned violation of first come first served, based on the assumption that no reasonable person thinks a child buying a candy bar should wait behind an old man stocking up on provisions for the Mayan apocalypse.
Surveys show that many people will wait twice as long for fast food, provided the establishment uses a first-come-first-served, single-queue ordering system as opposed to a multi-queue setup. Anyone who's ever had to choose a line at a grocery store knows how unfair multiple queues can seem; invariably, you wind up kicking yourself for not choosing the line next to you moving twice as fast.
Alex Stone is the author of "Fooling Houdini: Magicians, Mentalists, Math Geeks and the Hidden Powers of the Mind."