School milk, glad to see I'm not alone on this one. Alas! Margaret Thatcher (aka the milk snatcher arrived too late for me) I still can't drink milk on it's own.
School dinners - milk puddings with lumps, mashed potatoes with lumps, which we were forced to eat.
I wasn't really aware of human rights then, but I always had the subliminal feeling that being forced to ingest anything unpalatable was some sort of abuse. The spurious argument that there were starving people in the world was frequently used and so the premise was that if we ate everything put in front of us that somehow mitigated that, but I couldn't work out how 
Catechism - forced to be word perfect by age 7ish, not only a fearful experience but a horrible waste of school time, at least learning times tables by rote could be put to good use throughout life. Catechism only ever amounted to a very long garbled meaningless mantra.