In the "comments" section of my previous post, I was repeatedly congratulated for my restraint in not offering the erring English teacher a hearty punch in the face.

That would have been a very unlikely outcome. Even if he'd gone beyond telling me that "Americans sound dreadful" and ventured into "your momma wears army boots" territory, I wouldn't have offered him physical violence.
I'm from the "stern glare and sharp retort" school of martial arts.

And any stray temptation to resort to administering a good old American knuckle sandwich would certainly have been crushed by the possibility of getting six months in prison. That's the new penalty under French law for assaulting a teacher.
I know about this because our houseguest this weekend is a recently retired collége (junior high) teacher and he keeps up with the latest news. Apparently, France has crazy nutjob parents (or 'parents fous de noix de travail' which makes absolutely NO sense in French, btw), just like the USA and a few French teachers have been punched out in the playground. No wonder people are so freaked out about "Americanisation"...