An American, an Englishman, and an Irishman walk into a bar. Each one orders a pint. Three flies land, one on each glass.

The American gags and pushes his drink away. The Englishman shrugs, flicks the fly away, and drinks the beer. The Irishman picks up the fly, shakes it up and down, and shouts, "Spit it out, fucker!"