5 REASONS PEOPLE DON'T WAVE BACK

  1. They're dicks
  2. You're a dick
  3. They're afraid they'll crash
  4. They're wondering why you're waving at them
  5. They have things to do
  6. They're simultaneously jealous of and mesmerized by how good your gluteus maximus looks in Lycra
    Suggested by   @aro