(~3 foot) Boa constrictor snagged me once but not serious. Turns out some rodents (fed live to the snake) can get harmful to the snake if the process goes wrong. To lessen that, I used to hold the rodent by the tail and dangle said poor creature. At one point, hamsters were a better price than full grown mice, but they don't have enough tail to grasp, so I would feed them to the snake by holding the back end of the body. this one hamster jerked to one side just as the boa struck, grazing me; healed fast.
I made a point of getting the snake out of the aquarium by having my hand go low and approach from the side, though sometimes she would hiss her concern for her safety, more so during a shed (eye caps get cloudy). Their sense of smell is good. One can tell when they first sniff dinner.
I caution everyone about keeping snakes though. So many wrong reasons, eventual loss of interest, pythons getting so big. They can live a long time. They could be considered a philosophers pet, given that they seem to spend a lot of time thinking. The central american boa I raised from a pencil neck was a sweetheart who liked people. Two redtails I had wanted to avoid humans. A friend with a burmese that had free reign of the bathroom used to climb in the bathtub/shower with me when I used it. But there were complications later with other people. The same friend also had a reticulated that deserves its own post...