I've been playing in bands for 40 years, and in that time I've never been in one that even DISCUSSED "tuning down." Now, it seems that it's fairly common. What's the deal? Is it so they don't have to play barre chords? Is it because they wan't the fatness of an E chord but can only reach a D vocally? And why haven't I heard about anyone tuning UP? I don't understand. Enlighten me.