Kids want to try everything
Kids want to try everything, experiment with different ways of being. Some people, even people with kids, don't know this. They'll observe my kids doing something good, like reading, and go on and on about how their kids don't read, they want to watch TV. Kids respond really strongly to peer models, and they want to try everything, experiment with different ways of being. All you're doing when you talk like that in front of my kids is planting the idea that they should eschew books and watch TV. Fortunately that's not going to happen, because they're book addicts, and we don't watch TV. At all. But think about what you're doing.
Here are some other things not to say to my kids:
"When I was a kid, I couldn't wait until summer, because I hated school."
"Do you know girls have cooties? Haven't gotten there yet? Believe me, you will."
"Are you popular?"
"Are you going to have a nap?"