To have loved and lost. I say this because I lost my true love and if I had not known him I never really would have been truly happy. He completed my life and even though he died and I lost him I still love him and can keep living since I know that is what he would want. If I had not experienced love I don't even know where I would be.
It can be hard to lose especially if it's in a cruel way, but it's always a learning experience which makes you a better person and is why we're here so I say to have and lost.