A cruel joke played on the residents of the great state of New Jersey, likely conceived by some wop from New York.
No one from New Jersey, or it's surrounding states (with the exception of that aforementioned wop), has ever said "joisey" in any context other than trying to explain that people from Jersey don't say joisey.
Ted: "Oh so you're from 'New JOISEY', eh? Hehehahalol"
Bill: "I'm going to murder that fucking wop. But first, let me grab a pork roll and cheese on a hard roll."