[alsocasey]

Right. I wonder what would happen if we try to include a measure of perceived fairness from the customer's point of view into this type of analysis. I always feel I'm picking the wrong queue at stores... single queues going to whatever cash is open seem fairer, if that makes sense.

[Someone]

Perceived fairness is very hard to quantify objectively. Is it fair if there are queues for people buying less than X items? If there are queues for people not paying cash? For frequent flyers? That you, by sheer misfortune, end up in the slow queue three times in a row? Should pensioners wait for people having work to do? Should fit people make room for the elderly? To what extent? Etc.

Instead, I think you should do the math; it will teach you that the probability that a given queue is slow is smaller than the probability that, given a person in a queue, that person is in a slow queue.

So, you spend more time in slow queues than in fast ones. Once you know that, train yourself to accept it.

[bostonvaulter2]

That's because if there are 4 lines there is generally a 75% chance that one of the other lines was faster.