Saw Ozzie and Sabbath a few times mid-90's thru '00s. One Ozzfest (I think) was headlined by Sabbath at Great Woods/Tweeter/Comcast center in Mansfield, and I was working at Tweeter at the time, so we always had access to great seats. This time I was prolly like 6 rows back, left side of the stage audience-wise. The guy I was with was my co-worker and the drummer in the band I was in, and he first pointed out a crazy thing like 2-3 songs in.
There was a dude counting off the time to Ward on his hands raised above his head, in front of Ward to his left, our right, shaded by the amps and risers and shit so most of the audience couldn't see him. A human fucking metronome. 1-2-3-4-1-2-3-4 etc. Mind-blowing and hilarious in the moment, especially since it has always been put out there that Ozzy has backing tracks and doubles and all that shit, but the drummer needing manual counting help? Never heard of anything like that in my life. Still hard to believe that a life-long, legendary drummer needed a counter like that, since that shit is so ingrained in them from early on. But there it was in front of us...