You must be physically fragile to be so worried about an adult man's head being cracked if it hits the pavement by extrapolating your brittleness on others.

Damn dude, you likely need to hit the gym or at least do some regular excercises. But I guess your excess fear stops you from getting into normal shape.

Either that or you were born physically disabled as well as being mentally disabled although that's been pointed out already from the previous paragraph.