I think they can feel familiar or comfortable with their caretaker but thats it. Im pretty sure they recognize people to a certain extent.
I had a boa for years that let me do anything to her but when I sold her the new guy was promptly bitten.
He was a smoker so I imagine smelled funny.Could have been a random action but I do think that snake recognize either familiar scents on people or some other clues.
dont discount the familiar as less then love. I think a comfortable snake is a "happy" snake.