There's one thing that fascinates me about kids. I actually only noticed it recently while watching my little son.
The thing is, kids do everything 100%. There's no multitasking, whatever they do, they only do that thing and they are completely focused on it.
My son doesn't even speak and probably only understands very few words, yet nobody else will listen to whatever you say like he does. Obviously that's only true when he is listening, when he's not, he's not listening at all. There's no pretending. You either have his undivided attention or you have none of it.