Nepal, Dec. 23 -- Have you ever noticed how you become a slightly different person depending on who you are with? With one friend, you're the careful listener. With another, you're the one who keeps everyone laughing. Around your parents, you slip into the dutiful child; at work, the composed professional.

It can feel as though there are many small versions of you scattered across the people you know. We may even question: are we sharing from one whole self, or are we giving away small fragments of who we are?

The 'Horcrux'

In an interview, the comedian Trevor Noah referred to friendship as "horcruxes," borrowing the word from 'Harry Potter'. In the story, Horcruxes are the objects in which Voldemort stores fragments of his soul to avo...