Amateur bodybuilding is solely about aesthetics and conditioning.
Pro bodybuilding is about freaky bodyparts.
Think hard.. if you follow pro bodybuilding at all.
Think of a sucessfull pro...
I"m sure a bodypart (or extraordinary physical trait) will come to mind
Let me help you..off the top of my head:
Ronnie Coleman: freaky back.. freaky bis.. freaky glutes
Kevin Levrone: freaky delts and tris
Flex wheeler: crazy bis and delts (outlandish symmetry)
Vince taylor: Crazy Arms
Andreas Munzer: comic book crazy conditioning
Paul Demayo: huge huge quads
Mike Matarazzo: huge bis and calves
Shawn Ray: uncontrollable mouth

.. no seriously: inhuman serratus.spinal erector detail
and the list goes on
~Narkissos