I mean the ones that bear no resemblance to how people function in real life.
The doghouse - dogs must never be left for even reasonably short periods. In real life people just do this without thinking to go shopping or work.
The weddings threads - the absolute 'your wedding your rules' mantra. You have a brother who has helped and supported you your whole life, who has looked after your dc and generally been a kind and supportive family member. No invite for him! We want no more than five guests!
Relationships LTB - for even small issues as though it's an easy and logical thing to do. (I know there are excellent posters supporting people to leave genuinely abusive relationships).