The line comes from Palmashow, the French comedy duo of Grégoire Ludig and David Marsais, and their sketch La réunion maternelle. In the sketch the deadpan delivery turns a crude verdict into a joke, and French meme communities lifted the isolated line for soundboards and reaction edits. It spread as a shorthand dismissal for anything judged worthless, from bad opinions to failed stunts. Its staying power comes from the casual ouais, which makes the insult sound bored rather than angry.