When I used to get out and wander around the desert I would occasionally come across a rattlesnake or maybe King snake. The rattlesnakes wanted to be left alone but would get PO'd quickly and became mean and potentially kill you. The King snakes were docile and a pleasure to come across. Pick them up, they wouldn't bite. You knew how they would behave. You could predict the behavior of each.
Simply put, you could TRUST them to behave a certain way.
