I have all types of different attitudes with my snakes. Some I believe have a certain temperament because of age but others I believe its because of human contact. My first snake I ever got was given to me at about 150 grams. I held her often and she is currently the sweetest snake I have. She has never hissed and doesn't mind being touched on the head.
My girls mojave as a baby was a nightmare. Extremely aggressive and always striking any chance she could get. She is now 400+ grams and has significantly calmed down with only light handling.
I just picked up a 2000 gram breeder girl and she is extremely defensive and will strike occasionally. She is way out of the "baby" stages obviously but still acts ski-dish, probably from not being handled.
In my opinion snakes have different temperaments and while I do believe they get calmer with age and handling. Some will just be nice or nasty regardless.