The line comes from South Park, where Eric Cartman uses his catchphrase to assert childish independence whenever adults or friends try to control him. It became one of his most quoted lines from the long-running animated series created by Trey Parker and Matt Stone. Clips and quotes spread through forums, early meme pages and reaction videos, turning the short outburst into a shorthand for doing your own thing. It remains popular because the attitude is instantly recognisable in a single second.