When they get their beers, they notice a fly in each mug.
The millionaire politely asks the bartender for another beer, then sips the new one.
The hard hat spills out just enough to get rid of the fly and quaffs the rest.
It’s now the cheapskate’s turn: He sticks his hand into the beer, grabs the fly by the wings, and shouts, “Spit it out! Spit it out!”