Pink Floyd Marlowe Theatre Canterbury 1968 just after Syd Barrett was replaced by Dave Gilmour. They were promoting the Saucerful of Secrets album and joints were being passed around the audience. It was a bit of an eye opener to this 17 year old.
I was dragged to the Rod Stewart concert at the Brighton Centre 1978' "Do ya think I'm sexy" tour when I was 11 yo. I didn't think it was cool then, and not even now
Europe - Brighton Centre - probably 86 or 87. They played The Final Countdown twice, which made me think that the first time was more like The Penultimate Countdown.