I'm guilty of having done one through five before I was a teen and though I never drove a car until I got my learner's permit, I had a go cart... And man she was fast...

Things I learned from these experiences:

1. Dripping, melting plastic makes a cool noise, and when it touches skin, it sticks, burns and scars.

2. Cut away from yourself, because a sharp knife can cut down to bone.

3. Throwing a spear is fun. Catching a spear is painful.

4. I took apart a lot of broken appliances, and even managed to fix a few. If it isn't broken, don't open it up.

I have a lot of scars from childhood.