Before you send the angry text, sit with it alone for ten minutes. The you that comes back is usually wiser.

Anger peaks fast and then drops faster than it feels like it will. At minute one you want them to understand how wrong they were, and at minute ten you want the problem solved. Those two aims produce completely different messages, and only one of them helps.

So put ten minutes between the writing and the sending, every time. Type it somewhere that cannot send, then go and do something physical: stairs, dishes, a walk to the end of the road. Come back and send the version the later you would write, which is shorter and gets more of what you wanted.