The line comes from comedian Steve Martin, who made well excuuuse me a signature catchphrase in his 1970s stand-up act and Saturday Night Live appearances. Delivered with exaggerated offense, it became one of his most imitated bits and followed him into film and TV references. Online it survived as a soundboard staple because the stretched delivery is instantly recognizable even out of context. Creators keep reviving it for reaction memes where a sassy, unbothered comeback fits.