Jamerson used to get up and walk out if he thought the Funk bros were being asked to do too many takes of the same track and say that "rig" (rigor mortis) was setting in...
Many say that Stevie Wonder's "I Was Made To Love Her" was Jamerson's finest moment. The verse structure is identical throughout, but Jamerson does subtly different things every time.
The consensus is that it was Jamerson. Babbit played on a few of Norman Whitfield's sessions (Ball of Confusion, for example), but Jamerson was always the first-call player - until the drink got the better of him.