My T has a knack of finding a natural place in the conversation to conclude and says "is it okay if we end there?" We usually chat a few more minutes, wrap up, arrange our next appointment etc, and at some point I hand my money over. Then she walks me out, and I thank her as we say goodbyes at the door.

I think I'd be a little upset if she abruptly cut me off in the middle of me saying something...