The think it’s the subversions that really stand out to me. There’s the subversion of the genre itself, obviously, where the party isn’t magically the most competent party in the world just for the sake of the story, but also there’s the subversion of Konosuba itself when the characters actually do get to show a reasonable degree of competence like during the fight against the Destroyer or Aqua’s takedown of Hans. It keeps the story from getting stale without contradicting the characters’ motivations and characterizations.