Sometimes, a wrestler has everything save the one ingredient necessary to be a star: the ability to talk.
It doesn't matter if you're a technical wizard (think a cross between Dean Malenko and Kevin Nash's Oz) or have a body that'd make gong-bonger Kenneth Richmond wince with envy, if you've a helium voice and all the compelling verbiage of a Love Island contestant, no-one's going to pony up dollars to watch you.
That's where the manager comes in, an elegant solution that masks an otherwise budding performer's weaknesses whilst maintaining the basic conceit of the sport. Brock Lesnar comes across as one of WWE's biggest badasses today, not only because he's some sort of human-horse hybrid, but because he never opens his mouth. Paul Heyman does all his talking for him - and you just about believe it.
Now imagine if instead of Heyman, 'The Beast' was represented by Harvey Wippleman. Remember how effective the similarly jacked Sid Justice was as a heel thanks to the Doctor's guidance? Of course you don't. Most barely remember they were associated.
As useless as Wippleman was, he at least served a purpose. Unfortunately, there have been times when superstars significantly more urbane than the 'Sycho' have been derailed by a pointless mouthpiece. And all of them could have managed just fine by themselves.