Last week I was in line at the supermarket when the person in front of me had one of those items that could not scan. The "need help" light went on, as the cashier waited for assistance for what seemed to have been at least five minutes. As the other lines speedily progressed, the person behind me exclaimed with a look of sincere curiosity and frustration, "How come I always pick the slowest line!?"
I responded, "Although it may seem that way, I would bet that you are making the best line choice given the available information which includes the number of people in each line, the number of items each customer has, and maybe a general (and perhaps inaccurate) heuristic telling you that the more 'mature' cashiers tend to be slower." I continued, "Due to something called the availability bias, you have more vivid memories of the times you chose the wrong line rather than all the times you chose the right one. This is why you think you choose the slowest lines, when in reality, you probably only rarely end up in the slowest lines due to unforeseen factors such as price-checks, customers running back for forgotten items, and customers paying with pennies."
After a long blank stare the person said, "That was actually a rhetorical question."
I swear that at least some part of this story is 100% true.