Twilight

Here is an experience I've had a few times:

I am at a concert, and a moving performance is about to come to an end. I suddenly feel sad. The sun is descending on another world, a world I had only one chance to experience, and soon all will be dark. At the same time, it is the end of the performance I've been waiting to hear. Now, the moment arrives, and I feel sadness and joy at the same time.

I believe that all of the most touching experiences in life are tinged with sadness. Something happens when joy and sadness are combined; the whole becomes greater than the sum of the parts. The closest name I can think of to describe this combined emotion is "the feeling of being human."