What's the difference between potentialy and reality?

Youngest Son: Tell me Daddy, what is the difference between "potentially" and "in reality" Dad: I will show you Dad turns to his wife and asks her: Would you sleep with Robert Redford for 1 million dollars? Wife: Yes of course! I would never waste such an opportunity! Then Dad asks his daughter if she would sleep with Brad Pitt for 1 million dollars? Daughter: Waoh! Yes! This is my fantasy! So Dad turns to his elder son and asks him: Would you sleep with Tom Cruise for 1 million dollars? Elder Son: Yeah! Why not? Imagine what I could do with 1 million dollars! I would never hesitate! So the father turns back to his younger son saying: You see son, "potentially" we are sitting on 3 million dollars, but "in reality" we are living with 2 bitches and 1 gay!