The line comes from Rick and Morty, in the first season episode where Rick builds a small robot solely to pass butter at the breakfast table. When the robot asks what its purpose is, Rick answers plainly, and the robot reacts with quiet despair. The exchange became a widely shared meme because it compresses an existential joke into a few seconds, and creators have reused it ever since for characters, pets, employees and gamers stuck doing one repetitive job. Its staying power comes from how easily that single question fits almost any pointless task.