I have done over 200 sessions and only stopped 5 of them because I was upset:

1. There was a case where the Domme did something I thought was clearly unsafe. I also suspected that she was high on drugs.

2. There was a really bad session for multiple reasons that I am not going to detail

3. There was another session that got off on the wrong foot over the presession instructions

4. There was a session where I gave the Domme clear instructions how to perform an unusual torment. She deviated from them and I threw up.

5. And there was another session with a different mistress and it involved the same torment. In three prior sessions she had done it correctly but this time she decided to improvise. The result was strong nausea. I thought I was going to vomit again but didn't. She did the right thing and said she felt bad about what had happened. I previously had excellent sessions with her and my anger subsided afterwards. I forgave her and we resumed doing sessions.

There was also a time where I grew upset during the session but held my tongue until I was dressing afterwards then let loose. The Domme was one of those that stays in persona afterwards and there was a lot of loud acrimony.

So that was my experience. I suspect there are categories of subs who get riled rather easily. One of them is those clients who try to badger the mistress into doing things on the "Don't Even Ask" list. Another category is guys who like to top from the bottom and get upset when the lady expresses disapproval. There are probably some others.