Was at fantasy/sci-fi writing convention last august. Was talking with a friend at the dealer's room and George R.R. Martin walks right past. I swear I ran into him more than anyone else at the con. He's actually a really mellow guy.
I spent many nights at SF conventions partying with George "Rail Road" Martin back in the 1980s. He's lots of fun.
I remember sitting through readings he would do of books he was working on before they were final, back in the days of Fevre Dream and Sand Kings.
He was always very gracious and friendly.
George R R Martin sat next to me on a plane to Seattle a few months back, right after the latest book came out.
I'm a pretty big fan so we ended up talking a lot of the flight about random things, including football (he's a Jets fan and I'm a Chargers fan, there's a bit of a rivalry). He talked a little about the new book and I asked him politely to not kill my favorite character.
I had him sign my iPad and it wasn't until later that I realized he signed "GO JETS!" on it :(
He was very kind to everyone and had a smile for me and everyone. It was a thrill to meet an author I adore
I was walking around at a convention a couple years ago, and saw him just ambling around. Being the ridiculous fan of both ASoIaF and Wild Cards that I am, I of course approached him and started talking to him. We ended up standing there for ten minutes or so, just standing in the aisle between two booths chatting about his various projects.
He has to get that kind of thing all the time (especially now that the TV show is so popular), but he was extremely friendly and seemed completely unhurried to end the conversation.