Waiting in line is a scourge of modernity. According to David Andrews’s book, Why Does the Other Line Always Move Faster?, it wasn’t common until the Industrial Revolution synchronized workers’ schedules, causing lines that gobbled up lunch hours and evenings. Given that Americans are estimated to collectively waste tens of billions of hours a year in lines, it’s no wonder that some people try to cut, and others bitterly resent them. Yet jumping the queue without inviting violence is possible. Below, some pointers, courtesy of social science.
First, pick the right queue. It’s virtually impossible to cut the line for a once-in-a-lifetime event—the Cubs playing the World Series, say. But in a repeating scenario like a security line, people are more likely to let you in, perhaps because they anticipate needing a similar favor someday. Using game theory to determine what conditions would make line-cutting socially permissible, researchers found that people queuing just once display little tolerance for line-cutting. But when the queue repeats, people let in intruders who claim an urgent need or who require minimal service time. 
An excuse for cutting helps, but it needn’t be bulletproof. In one much-cited study, experimenters tried to jump photocopier queues using one of three explanations. A small, polite request without justification—“Excuse me, I have five pages. May I use the Xerox machine?”—enabled them to cut 60 percent of the time. Adding that they were rushed allowed them to cut 94 percent of the time. And “May I use the Xerox machine, because I need to make copies?” was almost as effective, despite its flimsiness.