Painis comes from the Team Fortress 2 community, where fan-made freak characters like Painis Cupcake became running jokes in Garry's Mod and machinima videos. Clips built around the character's blunt, distorted lines were shared and remixed for years, and short approval lines were later lifted onto soundboards as standalone reactions. The phrase survives because it needs no setup outside that meme context, working as instant, ironic endorsement in gaming chats, edits, and comment threads where a serious voice approving something silly is the whole joke.