Torture and ritual humiliation for me, with the humiliation coming both from teachers and other students.
Huge focus on team sports and athletics, none of which I was good at, and total contempt from teachers and pupils if you weren't very capable. The thing that rankles most is that there was absolutely no acknowledgement that some people are good at sports outside of the very narrow window that school offers - I wasn't a quick runner but, once I actually learned how to run properly, have found that I am a good cross country runner, and I was good at horse riding and very strong, but there was no interest whatsoever in those things and I was made to feel useless. It fostered a loathing of exercise in me that led to my becoming significantly overweight and unhealthy from GCSEs through to second year of uni.
I've since found an enjoyment of exercise, and have swayed between being very slim and very fit, running half marathons and exercising daily, to nowadays when I'm not super fit but am healthy, not overweight, and walk loads and do more formal exercise a few times a week. I still get very anxious and self-conscious about exercising in a group, though. I won't even run with my DH. So I do think school PE was very damaging.
I found an enjoyment of exercise in 2nd year of uni when I realised I desperately needed to lose weight. It really highlighted for me how inadequate school PE was, though. I had no idea how to exercise effectively or run properly, once I learned those things everything became easier and I started to enjoy it. I have no idea why schools don't teach those basics, rather than just expecting kids to throw themselves round a running track with absolutely no foundation, then wondering why only the naturally able runners enjoy it.