The evil version of taking a self-care day.
A chance for a depressed person to abandon all commitments and responsibilities to do things that make them feel terrible.
Extra points if you take time off work or miss an inportant deadline.
Person 1: "I haven't seen you since last week, are you okay?"
Person 2: "I just took a self-destruct day. I slept for 14+ hours, then stayed in bed and rewatched episodes of the US office and ate so much food I couldn't move."
Person 1: "Bro, you need to go back to therapy."