9. Mr. Perfect (Coach)
If Mr. Perfect was as perfect as he claimed to be throughout his introductory vignettes (spoiler: he wasn't), he really didn't need a manager, but nevertheless he was initially paired with tactician par excellence Bobby Heenan. If that had been juicing a champion racehorse, when 'The Brain' assumed commentary duties to nurse a back in in 1991, Hennig's next mouthpiece effectively gelded him.
John Tolos was a respected veteran who'd competed with the likes of Gorilla Monsoon and Killer Kowalski during his heyday, but as 'Coach', the only thing he brought to Perfect's largely full table was incessant whistling (guess that made him 'one note'?). The classic sports motivator was of precisely zero benefit to Hennig in any capacity; the former could already cut a better promo than his new manager, and more often than not the Coach's antics distracted from his ring work.
At least a couple of Perfect's fellow Minnesotan's benefited from the association: over in Shaker Heights, The Beverly Brothers were gifted Hennig's old advisor, The Genius, as compensation for the Coach's poach. It's clear who got the best out of that deal.