The flute concert (old Loriot skit)
I love this skit because it really is true. Just imagine it’s at the opera instead. The last time it “happened” to me, a friend and I eyed the front row balcony seats (we were late to the game and got nosebleed seats). Unbeknownst to us, so did two kindly old ladies and an academic-looking couple, both of whom we ruthlessly guilt-tripped into moving over.
Until the real seat owners showed up. Then we all did the shuffle of shame.