I think people overestimate what our pets can actually do.
Yeah, I'd love to believe that my snakes care about me, if I left their life they'd be affected in an emotional way or are happy to see me when I walk by, but let's face reality here. Snakes have extremely small brains, and as someone had mentioned earlier their brains aren't made with the capability to feel emotion.

People mistake conditioning with trust or happiness, and their fight or flight instinct with fear or anger, these are instincts, not emotions.

If you want to do this with your harmless snakes, fine, but some quacks take it to the next level with venomous snakes and big cats.
There is nothing wrong with keeping an animal like that, but the second you start thinking the animal likes you and trusts you, you're a ticking time bomb for disaster.