There are so many sims now that behave mischievously even though they don't have a single negative trait!!! I hate this so much because I know every interaction can't be perfect but it's so annoying when you leave one of your sims unattended and they are actively sabotaging every relationship - including those with family members. Same with random sims. There are so many of them that do mischievous stuff and make your sims embarrassed or angry randomly. It's just way to common and I don't think sims should behave mischievously unless they have already built a negative relationship with another sim or have the trait like evil or mean (any negative ones). This has been a problem for too long!!😒
PS: I don't use Mods at all.
