ELI5: Explain Like I'm 5

why is it hip to be square

Being "hip to be square" is an expression that means it is cool or trendy to be different from everyone else. People who are square, or have unique interests, have a certain individual style that is respected and admired. This phrase came from a popular Huey Lewis and the News song released in 1985. It celebrates being different, which is why people think it's hip to be square.