When I was a teenager, I had the good fortune of attending a lecture by Prof. Nash. Although I did not have the maturity to truly grasp what he was trying to explain - the event did influence my later life. I started reading up about him and his struggles with his schizophrenia, the work he wanted to do, the fears he had of never achieving it, and how despite everything he ended up manifesting his work anyway. This influenced my own struggle with teenage depression and made me realise that there was probably more I could contribute beyond the seemingly staunch limits of my own mind. That altered my life trajectory in a "tiny" but measurable way, so that I - a complete stranger - feel moved by the loss.
I'm sure he stands for so much more to so many people and that's a testament to the power of a life well lived.