I wish I could have met Michael O'Hare after having seen the first season of 'Babylon 5'. I wish I could have told him that he had a real gift for playing the straight man; some of his best moments in the series come when he's playing opposite Jerry Doyle's Garibaldi, pretending to be oh-so-dignified and above this kind of silly behavior, but with a tiny little secret smile that lets you know he's in on the joke.
I've said in the past that I felt really lucky to be able to tell creators like Don Rosa, Gene Colan, and Al Feldstein what they meant to me and how much I think of them as creators and as people. It's always sad to realize that no matter how many people you can share that with, there are always going to be some people that you never get the chance to talk to.
Remember that, when you're at the next convention and you see someone you admire passing by. There's not always going to be the chance to do it again.