When I met an actual performance parent 
Not the ones who are just chatting to their children in a supermarket and are accused as such.
But one who was telling random strangers in a queue about how his 8yo has read the Hobbit (and his 8yo mentioned how dad didn't read it until he was 13!)
He was also getting him to give Harry Potter quizzes to the adults as he's a "Harry Potter genius" and this kid was loving lording it over adults he knew the answers.
We also had to listen to his jokes as he was encouraged to "tell another one".
I did the only thing anyone could do and turned to face forwards but listen in to the show going on behind me!
And now I understand what MNers mean when they talk about performance parenting at outdoor attractions!