Venting your anger on a punching bag makes you more aggressive, not less

Popular advice says to 'let it out' — hit a pillow, scream, vent. In a 2002 study, Brad Bushman had angered participants either hit a punching bag or sit quietly; the ones who hit the bag were later more aggressive toward the person who'd provoked them, not less. Rehearsing anger reinforces it rather than releasing it.

— Brad J. Bushman, Does Venting Anger Feed or Extinguish the Flame? Catharsis, Rumination, Distraction, Anger, and Aggressive Responding — Personality and Social Psychology Bulletin, 2002