1. Staying up late is an adult activity. Bedtimes are for little kids. Are you a dorky little kid or a cool adult?
  2. Enables you to procrastinate at any time. Whatever it is, you can always do it later. You'll be staying up late!
  3. Gives you an excuse to sleep late. Not that you really need one, but still.
  4. Encourages you to keep up with friends on the other side of the world.
  5. Fourthmeal, duh.