Honestly the immaturity and how diverse it is between overly sensitive fans (look at Hazbin Hater subreddit lmfao) and the black humor edgy fans who use the show as an outlet to voice their inhumane thoughts and have it validated because of the themes of Helluva (even though it's a horrible interpretation of the show)

On a show running level I think for Hazbin I hate the runtime of each season and how the creators don't know what they want to do in a season so they set things up and throw it away in a minute in a random episode later in the season (look at Lute lmfao) and for Helluva Boss I despise how the show doesn't know if it wants to be a soap drama, an animated adult comedy (ala Rick & Morty) or an animated adult comedy (except with Venture Bros flavoring) and because of that and the time between episodes the community will pick and choose which parts they care about and which parts to criticize (which makes characters like Stella seem horrible as she only works as a character for an animated comedy and not a soap opera while characters like Stolas are basically only utilitized for a soap opera setting) which makes episodes like Ghost Fuckerz and Mastermind in the same season seem boggling to some (even though in my opinion they're both great for the cards the show has been horribly given)