"I meet people and I can tell in two seconds whether they’re a rocker or not": Across 40 years playing music, here are 10 life lessons Dave Grohl has learned

Dave Grohl in Studio 666

That expression 'Don't judge a book by it's cover'? An important life lesson, one which Dave Grohl learned when he first saw his future Nirvana bandmates Kurt Cobain and Krist Novoselic.

"I remember being in the same room with them and thinking ‘What? That’s Nirvana? Are you kidding?’ Because on their [Bleach] record cover they looked like psycho lumberjacks! I was like ‘What, that little dude and that big motherfucker? You’re kidding me. No way...’"

Here are ten more important things that Foo Fighters' frontman has discovered during a lifetime in rock and roll.