Warren Ellis said this quote

Love is very important, nurse Igor. Love is a gateway emotion. Without it, you cannot fully comprehend and experience things like... vengeance, for instance. Or terror. Loss. Hate. Hate is all you need. Hate means never having to say you're sorry. You can't hate properly without ever having been in love. Because nothing will teach you hate as well as being in love. You can't understand a place without loving it. And it's the act of loving it that teaches you to hate it, as it chips away at your heart with its daily failures and disappointments.