From On Stage at World Cafe Live, episode 104 with The Knack, sometime in 2006 -- one of the brief backstage-chat clips inserted between songs. [Alas, I'm not sure which two band members are speaking here. If anyone can supply that information, I'd be grateful.]
"The classic stance on stage was 'angry young man', which worked for a couple of people 'cause they were really good at it"
"'Cause they were angry young men."
"But it got old, quick. And so we always made a point of ... not hiding what a great time you have when you get up and play. It's fun, it's a kick, it's what everyone wants to do. And that would always translate to the audience; the audience would be like one big grin coming back at us. And what I think is funny is, how many years we are down the line, and the classic stance is still 'angry young man'."
[Yes, I know, I should've had a quote from Paul McCartney for today. At least it's a rock-'n-roll quote though.]