Toss in excess sugar in the diet of most kids as well.
More often than not it is corn syrup rather than sugar.
And the fact that they don't let kids blow off most steam on the playground anymore.
I was talking to my 9 year old grandson. They won't let them play when it's muddy. They MAKE them wear snowpants if there's even a little bit of snow. They don't allow any physical activity on the playground like wrestling with each other. They don't allow baseballs or bats because they're too dangerous. They don't allow screaming or shouting on the playground. In short they expect children to behave like adults from a very early age ALL day long. And then they wonder why some kids are bouncing off the walls during class.