That’s a tough one.
One that sticks in my mind for being wonderfully dumb nerd shit was when I took an ex to see Breaking Benjamin (I was there mostly to see Sevendust who were playing mid-act).
It was the same year Force Awakens was coming out, so the band dimmed all the lights, walked out in full Sith garb, and ignited red light sabers while the bassist started strumming the Imperial March.
In terms of best live performances for me, that’d go to when I saw Tyr, Eluvite, and Finntroll. Was at a “little” venue, basically a bar with a big sound stage, held probably 300 people max.
But it was incredible. The acoustics were spot on despite the small venue size, and they managed to put on a hell of a lightshow (no pyro sadly). The lead singer of Finntroll was getting progressively more drunk as the night went on, and after their set was done wandered out into the crowd to watch Tyr and Eluvite play. So it was pretty cool to have see him just milling about with fans and rocking out with them.
I’ve been to much bigger concerts, with lots of pyro, crazy shit, and performances. I’ve seen Nightwish on a stage that moved, I watched a Bee Gees coverband rise from a literal cloud of mist, and I saw Sabaton bring out a fucking canon. But something about a super intimate, small venue where I was right up with the bands stands out as the best.