Mel Brooks had problems with Yugoslavian extras who did not speak English. Some extras playing museum guards were to walk through the museum ringing a bell and shouting, "Closing time! Closing time!" The extras misunderstood and walked through the scene shouting "Cloakie Bye! Cloakie Bye!" Brooks decided "Cloakie Bye" was funnier, so he left it in the movie.
Anne Bancroft encouraged Mel Brooks to write the music as well as the lyrics for "Hope for the best, expect the worst" and subsequently at least one song for all of his movies. She was 'like an angel on his shoulder' when it came to songwriting.