I was selling insurance under a new agent (who had just opened his own branch). His management style was abrasive and he worked through negative motivation, and I chafed under his style. But it didn't come to a head until a day he decided to train us in sales tactics for selling life insurance.
"Take cmc, for example," he noted, in a room filled with my coworkers. "If I were to sell her insurance I'd use her brother's death. I'd say to her" and he looked straight at me "do you really want your parents to have to stress when burying another child? Wouldn't you rather be a good daughter and make sure they don't have financial hardship stemming from your death? They'd be going through enough as it is!"
My brother had died shortly before that, and it was still a painful time in my life (why I shared that with him, I have no idea). I was so angry I sat in my chair, hands and jaw clenched, and said nothing. He kept trying to push at the 'sale' calling it "turning up the fire", and I just sat there in silence. Everyone in the room was visibly uncomfortable and he finally tapered off. The meeting ended and people filed out quietly, and we both stayed in the room.
"Uh, I don't think things are working out here for you" he began, and I was like "yeah I know, and it's a good thing you say that because I quit." I can't remember his exact words after that but it was something like "you can't quit, you're fired"...which is good, because then I filed for unemployment.
Within a year, his agency shut down. This was not his only glaring problem.