not everyone is the same and not every t is the same. I dont think anyone here is saying pain gives you and excuse yo hurl abuse at someone. That being said I find anger can be fascinating sometimes and hides a whole world, so I wouldnt terminate or be personally offended. Thos is especially true if the client was otherwise polite and didn't usually swear.
I was very angry growing up and pushed everyone away, what I know is that anger is usually there for a reason and the reason is so worth exploring. Everyone has their own boundaries and I have yet to see anyone say a T doesnt have a right to set his or her own rules for conduct.