Granted every snake has its own personality making some dolls and some devils, you can learn a lot about a specific species if you look at where they come from, what they eat, how they hunt, what eats them and if they are nocturnal or diurnal. Some species will be much more outgoing and inquisitive by nature and some will be more reclusive and less tolerant to interaction.
With most animals you can train past one instinct at a time but you cannot completemy change how an animal is wired. I would say you first need to decide what you want out of this new pet then decide what species is best for you based on that.