fairness · social · traps
Why your line is slower
The other lines look faster because you are stuck in this one.
You pick a checkout line at random. Other lines finish faster more often than yours does. This can happen even when all lines are identical.
Stand in a random line. Watch how often another line empties first.
There are more other lines than the one you are in.
Even if every line has the same average speed, the chance that at least one of the others is faster on this trip is greater than half.
Your memory also keeps the times you waited longer more vividly.
The feeling that you always pick the slow line is often the arithmetic of several lines, plus selective memory.