Zinnia, not trying discount how you feel but your argument for the possibility of snakes having emotions comes crumbling down when you realize that there is a physiological basis for emotion. Emotions are not just some thing that is floating around out there and takes place in humans and other primates (and maybe even other mammals). Emotions are produced in areas of the brain, and reptiles quite simply LACK these areas of the brain where higher-order reasoning take place.
That is fine-- but I am not actually trying to argue that reptiles HAVE emotion. I am arguing (but more musing than trying to prove a point) that maybe emotions are just a human construction. Maybe emotions such as we describe and believe we have-- are ONLY instinct and drive based reactions.

If that is true-- which I think it is somewhat-- then it follows that other creatures have similar instincts and drives so we could construct emotions for them just as we have for ourselves. My argument is that maybe emotions are just instinctive repsonses. We think we feel happy, sad, love, hate, but those feelings are related to survival and to feelings of security and stress.