Juno,
D'you know (Sorry he-he) that is an interesting last point. However, you can't even fart without it being in the SOP. I guess the reason why the whole personality/life experience skill is so important is because you spend an awful lot of time with just one person - especially on short haul.
You need to be able to engage in conversations/ discussions/ differences of opinion professionally so that after a stop over, there isn't any weird tension. Also actually having a personality is important when you are either in the cockpit or outside on a stop over.
I find it even more important when you are a 4-man (oops person) crew where the banter can be quite hearty in the cockpit and on the stop-over. You definitely don't want one person to be isolated throughout a 2-3 day trip.