Strong feelings are stemmed from events we experienced. Sometimes it manifests negatively, sometimes positively.
But you have to know that negativity and positivity balance each other, just like the sun and moon, and light and dark. So hating someone is as dangerous just as loving someone is, because the two are two sides of the same coin and can be flipped given the consequences.
Maybe one day, you might find yourself hating the person you love and loving the person you hate...