I have a rule to never send an email while angry. No matter how justified the anger is. There are no exceptions.

You know why, because you say things you'll cringe at later.

I have this really entitled coworker who gets angry over extremely stupid (and industry common) things. She is the type to believe that everyone else is an idiot but won't look in the mirror.

When she gets mad, she sends the most glorious train wrecks of an email. She thinks she's being stern and she thinks she's asserting some kind of authority in these emails. What she doesn't realize is that she is expressing hostility, emotional instability, and hurting her own future prospects over what amounts to spilled-milk type situations. It's a glorious trainwreck to watch.