Well

Hot-blooded badness, warmhearted goodness, and the unnerving incongruity of the cold-blooded versions raise a key point, encapsulated in a quote from Elie Wiesel, the Nobel Peace Prize winner and concentration camp survivor:

“The opposite of love is not hate; its opposite is indifference.” The biologies of strong love and strong hate are similar in many ways, as we’ll see.

- from Behave