Time and patience. BCC's are a little diffenent than BCI's. You "could" have an animal that will tame down slowly. Or, you "could" have an animal that will be nervous it's whole life. How are the parents? Are they tame? Or, wild caught?
Most boas will "tame" down with time. BCC's are a little more work IMHO. Some will be like BCI's. Others will not.
Just create certain "boundries" for you and your snake. These "boundries" can take some time. There is a fine line between not backing down from a hissing snake and where this will become detrimental. (ie. not eating, etc.) Each animal is different. You will have to gauge it's personality and see from there. I am sure even the "worst" snake will accept handling. How "trust worthy" it is..........Well, that's another story.
Snakes are like people in certain senses. Some are trusting. Others are not. Regardless of how much love and attention they get. It is a sad fact. But, it is the truth. Some animals will not tame down. Others will. And, some will be in that "middle ground". Hopefully yours will mellow with time and love.
John
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"To be the best..........You must lose your mind."