Sadly, I had a good friend have a serious enough health issue that he is unable to continue to game. It's weird, since he was the catalyst for a lot of the games we ran or played in, and had the best collection of foreign movies I've ever encountered.
For our group, whenever some new errata comes out we wonder what he'd think of it, since he was our resident WotC rules keeper.
All the time when I come across a particularly unusual film (Southland Tales being a recent example) I think about him and how I wish he were around to enjoy it with me.
Most of all, I just miss the good conversations about the future and the things we both want to do.
Both of us happen to be pretty religious, so I look forward to being able to have a game with him again someday. (Not meaning to offend ENWorld's ban on religion... I hope no one takes offense.)