Difference between potentially and realistically?

A young boy went to his father and asked; “What’s the difference between potentially, and
realistically?” The father replied, “Go ask your mother if she would sleep with Robert
Redford for a million dollars. Also, ask your sister if she would sleep with Brad Pitt for a
million dollars.
Then come and tell me what you have learned.” So the boy went to his mother and asked, “would
you sleep with Robert Redford for a million dollars?” The mother replied,“Of course I
would!! I wouldn’t pass up an opportunity like that!”
The boy then went to his sister and asked, “Would you sleep with Brad
Pitt for a million dollars?” His sister shouts, “Oh my god! I would just love to do that!! I
would have to be nuts to pass up that opportunity!!”
The boy thought about it for three or four days and went back to his
dad.
His father asked him, “Did you find out the difference between potential and realistic?” The
boy replied, “Yes.
Potentially we’re sitting on 2 million dollars, but realistically we’re living with two sluts”.