Do not vent your anger
Hitting a pillow does not release anything. It rehearses it.
Do this
When angry, do something that lowers arousal - slow breathing, walking, waiting - rather than something that expresses it forcefully. Address the grievance later, calmly and specifically, if it needs addressing.
Why it works
The catharsis hypothesis has been tested repeatedly and points the other way: people who hit a punching bag while thinking about someone who provoked them became more aggressive afterwards, not less. A 2024 meta-analysis of over 150 studies found arousal-decreasing activities reduced anger while arousal-increasing ones, including vigorous exercise in some cases, did not.
Where it fails
Talking about anger with someone who helps you make sense of it is different from venting it forcefully, and does help. Suppressing the emotion entirely is not the alternative being recommended here.
How you’ll know
Notice how you feel twenty minutes after venting compared with twenty minutes after walking. Most people have simply never run the comparison.