I truly feel happy when I learn something, esp. when a theory is substantiated via a series of events backed up by sound, creative engineering and science. Gives me hope that we're making another step away from irrationality. And the beauty and simplicity of the best thinking is astonishing.
Forgot to add this link: http://www.kurzweilai.net/scientists-create-femtosecond-atomic-x-ra...
and ask if others ever feel the same way.
Here's another one to illustrate the point: http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/
And to me it is cool that a prediction could be made in one era and tested several generations later - wow!