Longing

I read a post in which someone was giving notes from a talk they enjoyed, and at one point the speaker said something along the lines of "We are all searching to be happy.  All of the little sidetracks we take and the obsessions we cling to are all part of our search to be happy."

In a single world, a large part of our search for happiness comes from other people.
The desire for a relationship is a common topic of conversation.   From those who are interested in seven people to the one who complains about being unable to find anyone, everyone wants to find love.
It reminds me of a time someone was complaining about a Justin Bieber song.  She said that his lyric "I just need somebody to love" was terrible.  One shouldn't think that way, because just 'needing someone to love' means you are self-centered and hardly care about the other person as long as they fit your needs.
While her point is valid, and we need to make sure that we aren't "falling in love with the possibility of someone loving us", I think the mutual void is a significant driving force in bringing people together.
Something of an "I'm lonely.  You're lonely.  Let's be lonely together so we won't be anymore." type of deal.  It doesn't start out focused on the other person as a human whole, but if the relationship develops and the couple fights through the rougher times, it can flourish into a relationship in which each partner truly desires the fullest happiness of the other.

That being said, this driving void wields a large amount of power, and that power can drive people insane.  I wish it were not so, but I have some friends who have found 'the one', and have become so stuck on that one person that they cannot truly love anyone else.  It's obsessive and frightening, especially when a bad end causes someone to be so devastated that they start considering horrendous options.
On a less grand but just as damaging scale, I've met people who are so thirsty for the love they've tasted that they'll define their existence by their relationships.  Unstable when alone, they flit from relationship to relationship, desperately holding on to each partner and quickly finding another one when a schism occurs.  Consequently, complications abound.  They have many a story of an ex to tell, and when back into the searching phase, they have to keep all those names and details straight.  Even when in a relationship, there is a distinct possibility that the partnership could be lacking something a previous one had, yet they don't want to leave the relationship for fear of being alone.
Finally, there are those like me.  The love of a relationship (and consequently loss thereof) is unknown to me.  I subsist off of listening to songs and hearing stories from others, satiating my want for a relationship vicariously.  My imagination takes off at the merest hint of possibility until it knows exactly what we'll look like after being married for 23 years.  It's a dangerous game that can easily push me off the edge if things start spinning too fast, but it keeps me safe from danger in reality.

Neither side of the spectrum is really happy.  They are left wishing for what they once had, and I am left wishing I knew what it was like.  It makes me wonder if people ever really fulfill the longing that eats away at them, or just get so tired that when something could possibly work long-term, they take it up just to get the monster of hope out of their heads.