The differences between individuals are the causes of the greatest joy and suffering that exist in life. The fact that opposites attract is only interesting because of the fact that we like something that is inherently contradictory. This contradiction goes far beyond good girls liking bad boys, there is actually a biological tendency to be attracted to someone with differing genetic codes (they actually smell different depending on your own genetic code). This tendency has profound implications, we cannot be harmed by those similar to us, by their very nature they resemble us and thus we can't blame them for their actions, not only that but their actions were anticipated by us because we would have done the same and thus are not surprising. This surprise is the worst part of any action that hurts us, the fact that we didn't see it coming.
That is why relationships are best served when they are with individuals that we cannot understand. Because the greatest pain and suffering exist from those we cannot understand, however the world is not all dark thus, the great joy and happiness exist from those we cannot understand as well. I often deny the existence of love, and in a conventional sense i am correct, love doesn't exist (at least for me) in some emotional experience, it only exists as a capitulation of yourself to another. This is neither good nor bad but is unique, therefore the greatest joy one can experience in a capitulation of yourself to another completely.
This discussion has multiple reasons for arising, one is my neighbor and all that has happened, another is the fact that i have a letter lying on the counter at home. Opening up is often stated as something good, i disagree, however this is my only justification for that letter, my happiness and others. Capitulation to something greater than yourself is the truest form of joy because you can never be happy doing what you would naturally do, happiness or sadness can only arise from a change on yourself by yourself (the existence of this ability is something i will discuss at a latter date). Sometimes (as i watch the matrix) ignorance is not bliss, and truth and happiness are not mutually exclusive.