One of my personal favorites. That instead of paying full price to play "Marvel vs. Capcom," air hockey or that mini basketball hoops game, you realize the guy who played before you either: a) accidentally put in another quarter or two when he/she wasn't supposed to, or b) basically ran out of change to play another game. But God bless you!!
And if you don't play arcade games, imagine a kind of glee that's similar to pulling up to a parking meter with just enough minutes left for you to run into the bank and make that deposit.
Seriously, a quarter can still go a long way.