Why is the $20 bill still on the ground?

An old joke describes two economists walking down the street. The first one looks down and exclaims, "There is a $20 bill on the ground." The other one turns to him and says, "That's impossible. If it were there, someone would have picked it up already."

The joke reveals an important insight from economics—if opportunities are attractive, someone will seize them rapidly. The joke also raises an important question: If this really is a golden opportunity, why hasn't someone seized it already? Of course, someone has to be first! But, given the huge number of entrepreneurs in the world, the odds are very low that it is you. So, you have very little time left. Take the plunge!