I have this female friend that I "use" to measure how good my songs are (I don't make metal, but more pop'ish rock stuff), because she is kinda on the target audience. I was playing some of my riffs around for this female friend of mine unplugged with my guitar one day, then suddenly with one riff she said "that one sounds kinda nice". I demoed the riff down a moment ago, it was this. Well, it was one of the riffs she liked the most. The sad part is that it was the same four chord progession (but with a small twist) as on 90% of the big hits, like Lady Gaga's Poker Face. I, V, VI, IV. They fall for it all the time