Some say anger, some say love, I say both. They're two sides of the same coin, so to speak. Although, I do suppose hatred is the opposite of love in a sense, but the fact is, hatred usually has anger involved in it, thus I say anger. Love on the other hand is the force opposing anger and hatred in the way that you can't have both love and hatred at the same time, you can't love something and hate it, although, you can be angry at someone you love, in which case hatred again becomes the one involved.
So, overall, hatred and love.