
This is Bill Ward explaining why he called quit Heaven & Hell (essentially it was artistic differences with bandmate Tony Iommi) to Blabbermouth:
But the main reason inside everything was that Tony, on one of the songs, it was a pretty fast song, was pushing his guitar — it was just like a down beat — and in all the years that I’ve played with him, since I was, like, 16 — me and him have played together a long, long time — I’ve never cut across him. In other words, I never go through him — I don’t travel through him, I travel around him, and I either build or I pull away, or I make holes, or I do whatever I can do to make sure that I am interacting with the bass and the guitar in the way that I do it. It was requested of me to play a straight beat through, and playing a straight beat through was absolutely against everything I know about drumming, and it was an intolerable request. End of story. I can’t do that, and I’m not gonna do that to Tony. He’s a man that I love — I’ll love him for the rest of my life; we’ve done so much together. But I could not adhere to the track in which it was being requested of me. I need to go with him. So if he’s punching, I punch with him; it’s just a natural way that I play. I never go through him like he [doesn’t] exist. To me, what was being asked of me was disrespectful to Tony as a player. So I didn’t do it. I won’t compromise my sensibility… and my sensitivity, either, in music. So I just couldn’t cut it.
Surely, you’d think “we just didn’t like each other’s ideas” would work a lot better?