I went to a soccer match in Seoul! I drank Cass Lite and ate ddeokbokki (spicy rice cake, 떡볶이). There were fireworks and cheerleaders. The paper noisemakers were very effective.
Seoul World Cup Stadium seats just over 60,000 people, but obviously it wasn’t packed when we went. Still, super fun experience. Not Korea baseball level fun, but I do like soccer, so I’d go again.