From Gavin De Becker, The Gift of Fear: Survival Signals that Protect Us from Violence (1998):
"That's true," she said. "Every day I have to predict what the kids will do, and I succeed for reasons I can't explain." After a thoughtful pauses she added: " But I can't predict the behavior of adults."
This is interesting, because the range of behavior children might engage in is far, far greater than it is for adults. Few adults will suddenly throw something across the room and then break into uncontrolled laughter. Few women will, without apparent reason, lift their skirts above their heads or reach over to the next desk at work and grab the eyeglasses right off someone's face. Few adults will pour paint on the floor and then smear it around with their feet. Yet each of these behaviors is familiar to substitute teachers.
What is the meaning of the sentence placed in bold?