Mine really only talks about clients that he has written about and/or has permission from. And he doesn't do it that often. He certainly hasn't vented though. Only mentioned bits that illustrated something relevant.

There are times when I can see that he's had a hard day and just say "Hard day?" when I'm walking in. He'll acknowledge somehow but not say anything and doesn't seem to be distracted once we settle in.

He has had to excuse himself for a call that he took outside. I could kinda hear that it really wasn't going well. He just apologized and said that he had just spoken to infuriating parents. It was the only time he showed a sign of feeling frustrated and a little flustered.