fellow doll collector, i can confirm that bratz collectors are hell to deal withI'm a doll collector, and I don't know if it counts as a fandom but Bratz collectors are TOXIC. They're not as welcoming as the Barbie collectors and so many of them just make excuses for scalpers acting like paying $800 for a mass produced doll is 100% reasonable.
With K-Pop, I don't think Mamamoo fans are the worst, but I've seen some with superiority complexes. I just think it's funny when they feel so different and intellectual listening to Mamamoo when like it's literally just K-Pop. It's not that deep lol