The line comes from Major Payne, the 1995 military comedy starring Damon Wayans as a tough Marine drill instructor sent to whip a group of school cadets into shape. In the film, a young cadet's earnest attempt at a formal sir, yes sir comes out with a lisp, and that small mispronunciation became the joke people remembered. Shared as a short soundboard clip, it spread through memes and reaction videos as a shorthand for eager, slightly ridiculous obedience, which is why creators still reach for it whenever a yes needs to sound both loyal and funny.