Many opposites are not nearly as different as they first appear. For example, as Nobel Peace Prize winner Elie Wiesel observed, the opposite of love is not hate, but indifference; for at a minimum, to love or hate someone is to have intense emotions toward them. We see how the similarities between love and hate often outweigh the differences when one is transformed into the other, a phenomenon that literature — from Gilgamesh to Shakespeare to Harlequen Romances — has exploited and explored for millennia.
The psychological proximity of love and hate is part of the hard wiring of the human psyche. Dan Gilbert explains, in his book Stumbling on Happness, that the same neurocircuitry and neurochemistry triggered in response to stressful events ("fight or flight") are also triggered in response to sexual arousal. As a result, when we are stressed in the presence of a person we find sexually attractive, we have a tough time telling what we are responding to: are our passions inflamed (hate) because of a stressor, or are we aroused (love) because of the attractive person?
In the 1994 movie Speed starring Keanu Reeves and Sandra Bullock, Bullock's character, Annie Porter, appeals to this possible confusion when she notes, upon finding herself in the hero's arms after several near-death experiences, that "relationships that start under intense circumstances, they never last."
Call it an "emotional paradox": two very different dispositions — loving and hating — can have far more in common with each other than a seemingly intermediate state.
— Michael Raynor in his business book The Strategy Paradox. His thesis is that the strategies with the greatest possibility of success also have the greatest possibility of failure.