God, yes, I hate it when they randomly pick the same actions over and over again. I have one Sim who constantly picks chatting, sometimes even abandons specific tasks because she wants to chat. I always have to abort that. I don't mind a mischievous or evil Sim trolling in forums because it fits their personality, but pretty much all of the others do that, too. I seriously consider locking their own computers for them unless they really have to do some work on the **bleep** things.
I also don't get why some Sims pick up hobbies they absolutely hate. If they do it long enough, I'll get the popup saying "The Sim has discovered they actually like this hobby. Accept change?" - I more often than not click "no" on that if it doesn't fit the Sim at all or contradicts the settings I chose for them in CaS. I don't want all my Sims to love videogaming when they're not even a geek.
It's especially annoying when they start doing random stuff during social gatherings, like a wedding. I had a Sim do situps and pushups during a wedding reception but then, weddings are still pretty buggy. I also hate when they start cooking or baking at another Sim's house, and most of the time they make that awful white cake. Same with nannies.
I don't mind my Sims doing stuff on their own becaause very often, they end up doing hilarious things, and I've had very funny interactions between two or more Sims. At the same time it can get really annoying if they do the same three things over and over again, especially since almost all of them end up choosing computer-related activities.
I haven't had much funny interactions between my sims in Sims 4 I'm afraid, they do talk though, I don't mind them doing that. And I do like that Sims 4 is probably the first one where they can take care of their needs well enough and go to work without paying attention to them.
Sims 3 seemed to have been the peak for me when it came to unexpected sim interactions, one was a full on masochist. He kept trying to flirt with the evil mean woman in the same house, and always she would slap him or beat him up as a response. One time he even flirted with her AFTER she just beat him in a fight. I never told him to do that, or told her to respond that way. They just did. He never made a pass at the good woman in the same house. Which did fit with his rockstar personality. Sims 3 only got bothersome with some interactions added by social clubs through university. Anyone with a point of nerd cred would keep trying to berate everyone for their ignorance.
But back on topic, I think it could help a lot if sims just never did anything they dislike unless their life depends on it. Then you'd just have to set them to dislike mischief and video games to mostly leave computers alone. As it is I honestly don't see why they even bothered adding the whole like/dislike system if it only provides a small positive or negative moodlet when sims do it instead of affecting their behaviour at all of how much they would do it on their own.
