That's where the money is

A catchphrase is a phrase recognized by its repeated saying. You know, stuff like, "I pity the fool" and "I'm smarter than the average bear!". Such phrases often originate in pop culture and in films, television, and literature. If a catch phrase is "catchy" enough, you'll hear people quoting movies and t.v. they've never seen. Do you know anyone who's said "You talkin' to me?" but has never seen Taxi Driver? Has this person ever even heard of Martin Scorsese? Catchphrases are great because they do a lot of different things, whether it be an introduction like "This is American Idol!" or a substitute for a swear word, like Homer's "D'oh!". Or, catchphrases can mean literally nothing, like Larry the Cable Guy's "Git-R-Done!" 

Characters are also defined by their catch phrases. In the sitcom The Big Bang Theory, Sheldon Cooper is famous for his catchphrase, "Bazinga!". Sheldon utters this phrase as a way of saying, "Gotcha!" to people he has just one-upped and that shows his smug personality. In the sitcom How I Met Your Mother, the character Barney Stinson has a myriad number of catchphrases that show his adventurous, if not womanizing personality. Barney says "Suit Up!" when he wants a person to dress like him to go out. Barney also uses "Legendary!" to describe stories or schemes he concocts to get with women at the bar.

Catchphrases are cool because people use them in everyday conversations. You can't walk by two people talking without hearing a famous catchphrase from a popular episode of a television or a current film. If you listen close enough, you can maybe hear a catchphrase from an English teacher used to put emphasis on something. The point is, catchphrases are great because they are catchy! If a phrase isn't catchy, it'll never be popular. That's where the money is.