It's what the "groove" of a riff is made of -- together with the micro changes in palm muting, the way the pick is held and used... these make up the Metallica

It's what the "groove" of a riff is made of -- together with the micro changes in palm muting, the way the pick is held and used... these make up the Metallica sound the way it is. More in general, it's absolutely wrong to think that modern music, especially rock, is adequately represented on a score or tablature, there's so much missing information on timing, volume, color...