you don't have to be a parent to be STUPID.
I have them tailgating my trailer all the time. Or the brainsurgeons who cut me off then stop short in traffic. Or the genius who has a flatbed truck with his dog scrambling to stay on as he rounds a corner. Or the guy who popped his left tire, then pulled over, and rested the jack on the pavement and proceded to wrestle with the lug wrench while standing in traffic, or the people who change their tire to the donut, then drive that until it goes flat, or the guy who passed me as I stopped for a red light yesterday -- crossed the double yellow into oncoming traffic to get around me. I caught up to him at the next light 1/2 mile down the road.
The world is full of stupid people. Unfortunately, Darwin has been vexed.
If you don't know your costs, you can't bid right. If you don't bid right, you can't make money, If you can't make money, become a Wal-mart greeter.