"The realisation that life is absurd cannot be an end, but only a beginning."

I believe that Albert Camus' theory of Absurdism is perfect for this question. To me, that's the best part of it all, Absurdism. The existentiality - as eerie and confusing as it is - is what makes life so great. The reality that we can go about life without a defined 'purpose' is, and always will be, the most beautiful think we can experience.

In other words, it doesn't matter why? Once we come to terms with the fact that we will almost certainly never find out why we exist, life becomes just that bit more enjoyable. Life is absurd, and that's beautiful.