François l'Embrouille is the obnoxious, overconfident character played by Belgian comedian François Damiens in hidden camera sketches where he provokes strangers and officials with absurd confidence. The line comes from that world of deadpan confrontation, where the character refuses to take any situation seriously. Clips of Damiens were widely shared on French speaking video sites and social networks, and short excerpts became reaction sounds. This phrase survived because its meaning is clear even from the tone alone, so editors reuse it whenever a character needs to shrug off pressure, blame or bad news.