Little things that hurt like hell

Why are they so horrifically painful
  1. Cracked lips
  2. Hangnail
    So bad. Ewww.
  3. Burn
    However small.
  4. Splinter
  5. Paper cut
    Especially on loose skin.
  6. Scratched cornea
    Just no. No.
  7. Betrayal
  8. Lego underfoot
    Pure. Evil. Child friendly Evil.