Re: Describe your worst sparring experience...
I had sparred a few times with a friend who was an amateur and first instructed me, and he mostly went light on me. He was very into stressing fundamentals, and never stunned me too badly. When I first went to my gym and sparred for the first time, it was against a guy naturally bigger than me who was also a puncher. He said he had broken his hand, so I figured we'd be sparring relatively lightly. When I threw the first jab at him, he slipped it, and in slow motion I saw him come at me with a furious hook I could do nothing about. It clocked me hard. I had no idea he was going to come out that hard. I became more cautious, and eventually figured I'd have to hit him hard back, but it just gave him more opportunities to hit me with huge shots I didn't see coming (because of my eyes closing and especially because of the headgear.) My coach stopped it after he saw I was so dizzy. I never had problems sparring with anyone else in the gym, and I never understood why this guy had to hit like that when it was clear I had less experience.
One thing that worried me in a kind of ironic way was when I found out I could take those kinds of shots. They hurt like hell, they blurred my vision, they made my brain feel like it was swelling out of my skull, and yet I never felt like my legs were about to give or I was about to lose consciousness. It might have been easier to have found out I was glass-chinned and merely needed to avoid getting hit at all costs, but the risks felt very real once I found out these bombs weren't about to put me away. Fortunately, I got better, and have never gotten rocked like that since.