My ex once took me to see some small band I can't even remember the name of because it turned out Robert Plant was the opening act. He was secretly opening so he could test out some new material he was working on (Saving Grace) without precolouring people's perceptions, but he was also Robert Plant so he blew the crowd away. I felt genuinely bad that a bunch of young twenty something's had been put in the position of having to follow up on one of the greatest singers of all time. I remember them being fine, I might have enjoyed them in another context, but the contrast in skill and experience was just insurmountable.