I volunteered to teach for a day at a local secondary school. During the lunch break I commented to one of the teachers that I used to love teaching, because I enjoyed having a laugh and a joke with the students.
“Ooh no”, she said. “You couldn’t do that now because parents will complain.”
I found this hard to believe, but asking other teachers and parents elicited the same response. It seems that everyone is worried about causing offence, or maybe just concerned about being accused of wasting time.