Human Behavior

Sacrificing other things in order to protect one’s important thing.
Is this the source of the human behavior?
R.M. sacrificed ‘indifference’ for his dearest friend.
Y. T. sacrificed ‘himself’ for himself.
F.K. sacrificed ‘the place where she belonged’ to earn decision-making authority.
F. S. sacrifices ‘others’ for the life of the only person she loves.
From: The King of Nabari volume 7th

The line from Tao Te Ching about gain and loss reminded me about this line from the comic book The King of Nabari. This one mysterious character analyzes the action of others in the form of sacrifice and gain. All of them have different values and different pasts, but they are all related in a sense that they all are sacrificing something to gain the other. Have I done any sacrifice to fulfill my desire? Maybe I have. But have not considered them as “sacrifice”. I mean what makes thing “sacrifice”?

I would like to study human behavior some day.