I'm glad that your buddy wasn't hurt. I'm sure it was really weird seeing him lowside in slow-mo like that. You were probably looking at him and yelling from inside your helmet; "hey, what're ya doin?"
Personally, I won't ride if I'm tired. This is bad because I'm always tired. Two jobs, and all that. Usually, one of my buds will call either at some ridiculously early or insanely late hour of the day to invite me for a cruise. Most of the time I have to politely decline. I have to be awake, or else I won't ride. Just riding in the street takes mega-concentration these days. All the minivandrivinmoms (sp intentional) aren't watching what they are doing. Where I live there are a lot of retirees as well on the roads, who have no business being out unsupervised, let alone behind the wheel of a 4,000 pound wheeled weapon. Canyon carving requires alertness as well. If I'm going to take the time to suit up, uncover and unchain the bike, and ride out to the twisties, I want to thrash the bike the way it was meant to be thrashed. 'Ya know?
"You have some options to choose from: You can lead, you can follow, or you can get out of the way!"