An analysis (with statistics) of why the express lane at the grocery store isn't always the fastest option.
You attract more people holding fewer total items, but as the data shows above, when you add one person to the line, you're adding 48 extra seconds to the line length (that's "tender time" added to "other time") without even considering the items in her cart. Meanwhile, an extra item only costs you an extra 2.8 seconds. Therefore, you'd rather add 17 more items to the line than one extra person!
Great, now I have to haul my abacus to the supermarket to determine which line to stand in. (via mr)