i once read a book called 'how not to ruin your band' or something like that. i've just tried googling for it without any success but that's ok as it is a deeply crap book and i wouldb't recommend it to anyone. it sets out to tell you how to form a band; how to choose its members. how not to screw it up. all of this valuable advice is informed by a combination of vague music biz talk and even vaguer psychometrics. these included a set of multiple choice 'personality' questions, the answers to which would tell you what instrument you were suited to play.
that was the kind of thing that led me to wonder if the author was just taking the piss. but of course we probably recognise the kind of thing he was on about, particularly if you reduce it to something like this -
singers - up themselves.
guitarists - up themselves, but louder.
bassists - boring. probably finds 6 strings too much of a challenge.
keyboard players - clever. really boring.
drummers - stupid. really not boring.
i could go on but you get the idea. and i've probably played with people who to some small degree have at times behaved in a way that might have had some of those qualities that their instrument befitted. ahem. but it's the stuff of in-jokes rather than anything that bears much analysis. mind you, i was always a crap guitarist...