Classic Film Influence - Gangsters

While I was doing some background research on Little Caesar, I came across an interesting bit in a book called The Great Depression in America: A Cultural Encyclopedia. The entry for Little Caesar discusses how the now cliched lingo for gangsters (mugs, flatfoots, moll, the goods, etc.), was taken not from real street talk, but from the imaginations of Hollywood writers. It's a good example of the enduring influence of Hollywood and classic films. Anybody have some other examples?

Above is Johnny Rocco (Edward G. Robinson) and his boys in Key Largo (1948).