The phrase not a morning person has long been used as a self deprecating label for people who struggle with early starts, and as a short audio clip it became a handy reaction for social video and messaging. Creators reuse the tired delivery to caption alarm clocks, dark bedrooms and slow commutes, letting one line explain a whole mood. Its popularity comes from its simplicity, since it fits school, work and weekend lie in contexts without needing a specific character, show or backstory to understand.