Does it seem like you never pick the "right" check-out lane at the grocery store -- other lanes always seem to move faster?

It is not your imagination. There are three factors that influence the speed of check-out lanes.

The first is that grocery stores monitor how many customers there are and only open a specific number of lanes, just enough to handle the flow. 

Why do they not hire more employees or open more lanes? It is a business, after all, and hiring more employees would mean less profit or higher prices for shoppers.

The second reason is that the odds are always against you. If there are three lanes open, you only have a 33% chance of picking the fastest one.

The third factor is our own fault. Stores like Best Buy and Barnes & Noble use systems where all shoppers get in one line, and the first person in line goes to whichever check-out spot comes open next. Mathematically, that is the fastest way to check out.

However, studies have shown that shoppers do not like that system -- we prefer to feel like we are in control, and picking our own lane gives us that feeling.

Read more: Wired

Photo credit: Shutterstock