Once, I was gonna do a punch in on 1 of the 24 tracks but forgot to disarm the other 23 tracks that were being used previously to record the whole band live.
BIG gap across all 24 tracks!!!
After realizing my mistake I quickly said:
Me: - Hmm, I'm sure you guys can do a better take, don't you think?
Band: - Yeah, you're right. Let's do another one!
Got lucky, and the band never knew what happened since I was alone in the control room.