I was told once at a job that if I got physical with a co-worker, even if I was justly defending myself from an attack, we would both be terminated, lol. Businesses who have "at will" employment relationships with you don't want any of your drama. They want you to fall in line, follow protocol and make them money. If you can't handle a douchebag getting in your face and insulting you without disengaging to management, customer service isn't for you.
It's honestly one of the reasons why I avoid customer service heavy jobs. My brother once worked in a ski resort restaurant populated by some rich better-than-you patrons. One of these folks decided to belittle my brother and insult him. So my brother bounced his chicken sandwich off his face while suggesting, "eat this you *#*#*#*#* *#*#*#*#*!" Thankfully he no longer works in customer service.