A clapback feels good for ten minutes. Staying above it feels good for ten years.

The perfect reply gives you about ten good minutes and then hands the argument back, usually with more fuel in it. Restraint gives you nothing now, which is exactly why it is hard, and then keeps paying out: nothing screenshotted, nothing to explain later, nothing you have to be the person who said. Years on, people remember what they did not send more fondly than anything they did.

Write it anyway. Type the whole devastating thing into your notes, because the satisfaction is mostly in the writing. Then close the app and go somewhere with people in it. Read it tomorrow and see if you still want it.