For sure an attentive keeper/breeder should be able to discern individual differences. I can and I'm sure you can but if you asked me for a confident young boa I would put a stipulation on 'it' because of how it is cared for here. Take a baby boa that is doing great in a rack system and place him or her in someone's idea of a display enclosure and all bets are off. Maybe that confident boa will adapt quickly or possibly not...-this is another part of keeping that requires attention to the individual and no individuality that I perceived can be a guarantee on the 'next step'.
I wanted to come back after reading my post and talk about why folks think a boa that has been 'worked with' appears relaxed/confident -because it works right!. The proof is in the pudding...Keepers handle baby boas and they continue to seem more at ease. -The reality is that they will get that way by leaving them alone too, maybe even sooner but who would know this? Only a few weirdo keepers that will only interact with a baby boa as little as possible.
Anyway, I'm glad you took that in the spirit it was intended rather than the cold text it that I'm good at amplifying.