roof, roof

Niki our dog was saying "roof roof" and I said "yes I see them on the roof".:)

Looking out the same upstairs window as yesterday, looking over our neighbor's roof I could see these guys installing an new roof on this neighbor's roof.
These guys need to be commended for the hard work that is involved in putting a new roof on houses. And it is dangerous. But these guys, and many other roofers like them, act like they are working on solid ground.

I was thinking why some people, such as roofers, steelworkers, window washers, and many other trades can walk around at great heights and are completely comfortable.
I think it's confidence.What do you think?