He never interrupted.
He never mocked or belittled ANYone.
He wasn't political.
He had a sexuality that made women swoon.
He had GREAT timing.
He loved discovering new comedians.
He was never threatened or jealous of up and coming talent.
He did a HUGE number of charity appearances.
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For the undiscovered, they were just supposed to do their act, and then exit stage left.
In was considered a major coup, if they could get Johnny to laugh. You could always hear the distinctive JC laugh in the background. Better yet, was to score such a success that Johnny would invite you over to the couch for a brief chat.