This proverb Jerry told was stated by someone else recently. The story of the flea. It may have been in a film. Jerry didn't tell it well at all.
Fleas jump two to three feet in the air. You put them in a jar with a lid, they jump and hit their heads on the lid. After a few times, the fleas will jump just high enough to avoid the lid. If you take them out, they will now jump to the same height as if they had the lid above them. But the story goes further. When they have children, they teach their children to jump just short of the lid, even though they may never be in the jar again.
The irony of this seems to me to say, take off the shackles of life and you can do anything. My thinking is he is talking about the Super Bowl in this chestnut.
However, the paradox is that Jerry has always been the lid on the Cowboy's jar with his demanding to be a football guy and GM.