Today, I heard a mother say this to her son:
'Look, a policeman! Go on, run up to him and give him a scare!'
Now, there's an example of a sentence which is only good parenting under certain very specific circumstances. About seven pm on Halloween; in a leafy middle-class bit of London, and when the son is four years old, and dressed as an adorable lion - OK. Pretty much any other time or place... not so great.
The other memorable sentence I overheard on my walk was: 'Ethan! Never mind about your sweets - just put your willy away!'