I think they they become used to the environment of being handled by humans and lose their fear of it.

I really don't think they can tell us apart though. Many ppl think that their bp knows them because it acts more comfortable with them... but a snake will be more comfortable with someone who is used to handling them and makes them feel more secure... ie. you.

I not much of a touchy feely guy I love my snakes but I really don't think they feel the same way. Thankfully I keep them in cages so they won't leave me... hows that for controlling!!

Justin