Why Do We Hide the Best Part of Ourselves?

In the aftermath of an unrealized love affair when you are left standing in the midst of the wreckage, the first question we ask is how did this happen?  Like accident re-constructionists, we rebuild the crash scene piecing together what forensic evidence still remains and then we use that information to try to figure out what went wrong.  One has this limited opportunity, this small window of time to put the pieces together and question what could have produced a much desired different outcome.
What caused this new hope of yours to find love again crash before it had the chance to grow?  Were you careless?  Did you not take enough time and effort to build a solid base?  Was he not interested or perhaps distracted by another? A myriad of possible scenarios play through your head while you try to make sense out of it all.  The questions are endless, but the trouble is you may never fully understand why this happened or what went wrong.  Often the answers we seek will remain forever out of our reach.
It doesn't mean it is fair; sometimes that's just how the promise of new love goes. We possess incomplete information.  Try as we might to understand every nuance of all the moments shared, we only have part of the story - ours.  Maybe this incompleteness is because we approach the chance to find love so guarded. We know pain and the older we get the harder it is to bounce back after an emotional setback.  So we purposefully hold back, because the stakes are so much higher now and whether we admit it or not, we are quick to cut the cord early and minimize our losses.  Therein lies the problem.
We all remember what it is like to go on a job interview, especially if it is a job we really desire.  In our efforts to land the desired position we put our best foot forward and give 1000% and maybe even make a few concessions along the way if it is our dream job.
Unfortunately many of us do not approach our search for love in the same manner.  We hold back - often out of fear of being rejected or disappointed.  We reveal just enough of ourselves to capture someone's interest, but then hold back the best part of ourselves as we try to build and maintain interest and nurture it along while remaining guarded and safe.  How misguided we are!
All many of us ever search for is that deep soulful connection to that one person who will intimately know who we really are.  Like the song says - "I just want you to know who I am"
I think that's all we can ever really ask of another.