Only Once. Not angry though. I had a flashback, couldn't verbalize it, felt overwhelmed and embarrassed, and walked out. It was about 20 minutes in and I pulled out my pre-written check (because I always have it ready) handed it to him and said. "I'm really sorry, I just can't talk today". It was fine, I texted him an hour later (per his request) and let him know I was okay. I would do it again if I had to.