I'm so mad at myself for only getting into them the last year or two. I'm with the 'thought they'd be terrible because of their costumes' crowd and ironically now I absolutely adore their aesthetic.
Ansatsu and mamimume monster-kun are my favourites!
Similar story to leafwork, severe depression / anxiety, left highschool and am now trying really hard to relearn how to be a person. As well as being diagnosed high-functioning autistic in my early teens.