I'd always thought that heavy metal - what I knew of it, anyway - was for tragic losers with acne and inch-thick glasses who fantasised about slaying dragons and riding Harleys, failing to realise at the time that the only loser was me. Fortunately, a good friend of mine played me 'Battery' from Metallica's Master Of Puppets album and the scales fell instantly from my eyes. It was a total revelation.