My favourite moment - Terry was in London for a few days which just happened to be the week that the Friday evening literary class I went to (run by John Clute) was reading one of his books. And by pure chance Terry phoned me on Wednesday, mentioned that he was at a bit of a loose end on Friday, and asked if I knew of any SF related club meetings etc. on the Friday... Result, Terry turned up for a 2+ hour Q&A session for about twenty people, and a very good time was had by all.
Neil Gaiman's thoughts here:
http://journal.neilgaiman.com/2015/03/terry-pratchett.html
WAY too young.