Being non-aggressive doesn't mean they're personable. That'd be like saying my deaf, blind, and mute grandfather is personable just because he's gentle and calm. We all know ball pythons are extremely docile most of the time, but their personalities can vary greatly.

I'm not saying ball pythons aren't personable, I'm just saying some are more so than others. And to breed out the lower stress bps would be a great project, being as stress has been linked to genetics.