I was thrown by this a lot more than I was expecting. This was the first time the news of the passing of someone I didn't know personally (eg celebrity) has actually affected me. I was rather teary all day, reading some of the beautiful and poignant things people were writing on Facebook, Twitter, Instagram; reading articles and editorials such as this one by the Discworld Emporium. Teary to the extent that I had one of those headaches that comes from crying too much.
Previously when people have talked about being upset when Elvis Presley died, or Princess Diana, Michael Jackson, even Steven Irwin, I couldn't understand it. They'd never met this person, they were just an image on TV or a picture in a magazine, a song on a radio.
Now I do. People we don't know, never meet, can still have a significant impact on our lives, and shape the person who we are.
Terry Pratchett was, is, and most likely always will be my all-time favourite author. His work came into my life when I was about 12 and awoke a love for fantasy and science fiction novels. They gave me comfort the year I lived in Malaysia as an exchange student - I'd allow myself to buy one new one each month and would read it over and over again until the next month when I could buy my next book. The Discworld shaped some of my travels and adventures while I lived in the United Kingdom, including trips to Wincanton (twined with Ahnk-Morpork) and over to Ireland for the Irish Discworld Convention. I often listen to the audio books when driving for work, or when dropping off to sleep at night - I know them so well I can lose myself in the book and turn off all other thoughts.
I never met Terry face-to-face, but I did have the privilege to hear him speak live once, at the launch event for "The Science of the Discworld IV". I've also met a lot of people who knew him personally, who were close friends, and on whom characters from the Discworld were based.
Now I know there will be no more new adventures on the Disc, and that's probably what makes me most sad. My brother posted on his facebook page: "There are very few Pratchett novels I haven't yet read, and will savour them all the more knowing they will be the last new journeys I will have into the wonderful mind of this magnificent man." I echo this sentiment completely.