I agree with being direct and assertive....

Although, I recall a time when I told my T that I felt that the topic we were talking about was a waste of time and that I didn't want to spend the session talking about it, and he explained why he thought it wasn't a waste of time....

I then explained that sure, there were valuable lessons there - but I made the EMERGENCY APPT to talk about SOMETHING ELSE!

He got the point....and we moved on......but he then found some way to interconnect the two issues.