"Have som personality please" by polarbearsims makes interactions in general be a lot more autonomous. And if sims are in a bad mood they often choose a mean interactions, and that turns into a mean conversation which often spirals even further. its quite fun to play with! Also, i played with a mod that adjusted hunger to turn you angry instead of comfortable and played with meaningful stories, so that contributed into them being angry moreoften
Another thing is if you have eco lifestyle and enable the roughhousing NAP they will probably fight more as well!