I agree that they dont actually get enjoyment from being handled. They can become use to it tho. They can also get use to your scent and they will know you are not a threat. My BP's never really calm down when they are out of their enclosures. They think its their time to explore and make an escape. Looking for a crevice to hide in. These are actually signs of stress or of not wanting to be out in the open..

On the other hand. I use to have a burmese that would curl up in my lap and just stay there until i put him back in his cage. Some days i would take him outside draped around my neck and shoulders and he would just stay there. Not even move except to turn his head and look around. He was very comfortable with being handled and very calm. He was like this at 1 foot long as well as when he reached over 8 feet when i had re-home him.

BP's are such naturally shy and nocturnal snakes, they rarely exibit this calm behaviour if they are out of their enclosure.