Customer....punch pow...chop chop?

You have the right to work and do your job without being hared and abused by customers. That being said, as an employee, you should never speak like this while you are on the job, as it is a poor reflection on the business to any other customers that may overhear. If you are in a situation where a customer is being rude and verbally abusive, and there is no manager present, you should CALMLY advise them that you will not be serving them, and they should leave the premises; if they refuse to leave, call the police. Now, as for your boss's reaction, you should explain to him that the customer upset you, and you didn't know how to respond, and own up to the fact that you reacted poorly. I'm sure you're not going to lose your job over this, but if you want to get back on your boss's good side, ask him for his advice on how to deal with difficult customers.