I feel really mad at this customer.
Why are you mad at this customer?
He is inconsiderate, rude, stubborn and always thinks he's right.
I can understand you getting upset at this customer for treating you rudely. Remember though that it's part of your job to stay calm even when a customer upsets you.
It's hard to be calm when someone is being shitty. They have reason to be angry since I'm being shitty to them.
I get that, but being upset about the situation isn't going do anything for you. If the customer is proving to be too much for you I recommend seeking out a coworker to see if they could take care of the situation.