This is an interesting story.
This guy has all the happy employees.He replied his self raised question by answering that to keep the workforce happy he fired all the unhappy employees.
I think this is a simple solution to keep the disgruntled people ruining the atmosphere of the work place.
Disruptive and crybaby employees ,friends, students are bad for health of others in any organisation.They bring the morale of the place down.
Children should be trained and educated to keep an upbeat demeanor so they may grow up to be happy and well adjusted workers and friends.