I usually don't have any issues with my sparring sessions at the boxing gym I go to, but this one might be worth mentioning.
Anyway, I don't own a set of headgear, so I usually use the community ones at the gym. So I'm boxing this guy when he hits me with an overhand right, bringing the headgear down over my eyes. I can't see shit, and he charges in and hits me with a barrage of punches. I try pulling up my headgear, but because it was lodged in pretty tight over my eyes and me trying to blindly bob and slip punches, I couldn't do it until our coach stepped in.
I shrug it off, thinking that maybe in the heat of the moment he didn't notice the headgear covering my face or notice me trying to wave at him to stop. I was surprised at the fact that he still kept on throwing hooks and whatnot despite me not firing back with anything or blocking much at all (i.e., as if I was hurt) during a light sparring session, since all of the folk at our gym tend to back off after they land a couple good shots when we are going light.
So we go again, this time towards the center of the ring where I get hit again and the headgear covers my eyes again. This time I back up and put one hand on the ropes and tell him to stop. I turn my back towards him thinking he was going to stop, to take a moment to adjust my headrest as he comes in and hits me with what I presume to be a couple of 1-2s to the back of my skull. So now I'm hurled over the ropes, with my left trying to cover the back of my head as he continues to throw at my back and my head. He finally stops once the coach steps in again.
I think this guy tends to get a bit too heated during sparring sessions since prior to sparring me, he went apeshit trying to punch out a 14 year old kid who was obviously hurt.