Years ago I had an experience that almost caused be to quit playing D&D. My DM relocated, so I had to find a new group to game with. I found a group, but I didn't really know anyone there. During the game, the party bit off more than it could chew, and we were captured. I was the only female player, and I played the only female character in the group. The DM proceeded to have our captors rape my character. He even pushed me to roleplay the scene, describing what the rapist was doing to my character and asking me what my character was doing.
I was horrified to the point of silence.
When I looked around the table for support, the other players just stared at me and watched as my face turned pale, glancing back to the DM as he described the "action." Once I realized that yes, this was actually happening and they expected me to be a part of it, I grabbed my stuff and left as quickly as I could.
It was humiliating, terrifying, and degrading (I could only assume they were imagining me going through what was being done to my character). In retrospect, I think I was very fortunate that I didn't suffer a real life assault that night. However, as fortunate as I may have been that night, it was also a very scarring experience that informs my decisions about playing with strangers to this day. That's how I almost quit D&D for good. . .