I was ready to lose my shit on them but my wife made me wait a day before responding when she saw how angry I was.
I was considering hiring a lawyer to sue the shit out of them for discrimination, but at the end of the day I brushed it off with a snarky "at least I'm experienced enough to double check who my illegal emails are going to" and told them I was reporting it to the Equal Employment Opportunity Commission (which I did).
This was years ago, and I've always been well employed, but I'm still a little mad about it.
I did find out through an acquaintance that the person who mistakingly sent that email was fired almost immediately and they were pretty worried about a lawsuit.
The struggle is so real. It's insane.