"I'll take my hand away from your face!" was always a good one. Take it away as much as you like - it's applying it at high speed that hurts!

Also: August, summer holiday, bright sun, 28 degrees in the shade - "Put your vest on! You'll catch Yerdetha Cold!" I always imagined Yerdetha Cold to be something exotic like the Hong Kong Flu or the Dreaded Lergi, because nobody died of a bog-standard cold!

Watching too much TV? "You'll have square eyes!"

My father used to call us 'reprobates', I called my kids that, and my grandkids also. So my eldest granddaughter says to her teacher "Miss, X is being a reprobate!" Teacher has to go and look up 'reprobate'. WTF?