I love queues. Not that I love queueing — I may be English but I’m not that English. But from a safe distance, queues are fascinating. They’re less fun if they cause you to miss your flight. In mid-May, two-hour queues for security at Chicago’s Midway airport had just that effect. Jeh Johnson, the US Secretary for Homeland Security, offered travellers some meditative advice: “Contemplate increased wait times as you travel.” I’d hope we can do a little better than mindful meditation.

There are three very different perspectives on queues: psychological, engineering and economic.

The psychological perspective tells us that much of what makes queues unpleasant is nothing to do with the waiting time. If a queue carries risk (you may or may not make your flight), then it is far more stressful. So are queues that are confrontational, unfair or require constant monitoring for queue-jumpers or the sudden opening up of new lines.