Their brains aren't like ours, but they're still brains - i.e, not computers and not something we actually understand very well at all. But I suspect that even very small brains can be much more sophisticated than we think.

We'll never know what it's really like to inhabit a BP's brain, but I think describing it as a world of instincts and basic visceral emotion (such as fear/anxiety, excitement, comfort, desire for particular conditions or mates or food) existing in the present moment is probably apt. That said though, whether or not they recall specific events in the past, they certainly can form associations and learn responses.

I also often wonder how much of their body motions are intentionally driven, and how much is essentially automatic. It appears that most of their intentional movements take place in the front third to half of the body, and the rest most of the time follows what the front did. Their caterpillar-type locomotion and also the lateral undulation type movement travels from the front of the body to the back. The rear third will tend to hold onto things if prodded or if the snake is starting to slip, but it's hard to tell whether that's really a reflex action or something the snake "decides" to do.

Brains are murky and complicated, even small reptile ones. We think ours are rational, but that is largely an illusion created by our complicated, murky brains.