Some people have a leg up on learning that lesson. Helen Keller understood that she needed her Annie. Alone, she was without sight or hearing, trapped in a silent, dark world which she could not understand nor interact with. The only way to compensate for the loss of those members of her body was to unite with another person. Tennis players won't get much preparation for heaven by playing singles.
Team sports can help teach interdependence.
Joe Montana and Jerry Rice helped each other to greatness. Baseball fans never give a thought to Tinker or Evers or Chance by themselves. Together, they were the premier double-play combination in baseball. God carefully and lovingly designed us to be dependent on one another and incomplete by ourselves. The ultimate example of this is a man and a woman coming together to create new life.