Hi all! Bit of a weird question, so I'll try to explain what I mean with my example.

I have a save where Jonah Powers is part of the household. For anyone that doesn't know, he's a premade university sim with only 2 points on the grouchy/nice scale. In my save, he's now an adult, and my approach to playing him was rather boring- I ended up playing him exactly like I do most of my sims (which is something I've been trying to change lately). I had him study and do homework in uni, I had him be friendly to everyone, didn't indulge his wants to cheat, and now he's a married adult with 4 children.

Now, when I take this Jonah out to a community lot and leave him to his own devices, he tends to be very friendly. Because he's very outgoing, he greets a lot of people, and it's extremely rare that he's rude to any of them.

So, one time, I was playing in a different neighborhood, and I decided to place a university lot. Then I realized, that doing that probably created a fresh copy of Jonah, and lo and behold, it did. I went ahead and booted up his household just to see what would happen, and wow the contrast is insane. Left to his own devices, this Jonah was an absolute menace, not only was he rude to Roxie's brother (which I expected as they have a negative relationship score), but he would constantly go up to strangers and pick fights with them over and over. It was honestly very amusing.

So I'm curious, what could be the biggest things I did that caused his behavior to change so much? I'm really curious, especially because I feel like most of my 'grouchy' sims don't act grouchy at all, and maybe it's partly my fault.

A good deal of it would be the training mechanism. Nobody knows exactly how it works, but the more often you direct a sim to do something, the more likely he is to do it again. So every time you cancel a grouchy action and substitute a nice one, you're essentially training niceness.

Even sims who are normally actively grouchy will usually be nice, and are often even superaffectionate, to sims they like, so the more friends Jonah has the fewer outright mean things he will do. The grouchiest man in Drama Acres, who used to go out of his way to noseflick people, and whose trashcan was almost always on its side, was extremely devoted to his wife and children, and never even raised his voice to them. I have even had grouchy sims who would give every impression of defending their friends when other grouchy sims picked on them, singling the offenders out to pick fights with.

Sims whose aspirations are good are less combative than sims in aspiration failure, so if you play according to wants, and particularly if you go out of your way to fill lots of high-value wants, antagonistic behavior will happen less often.

Some actions have grouchy ways of doing them, and these should not be affected. No matter how nice you've trained him to be, Jonah should still throw balls at people's heads when playing catch or tossing a football, and attempt to cheat at chess. I often think that grouchy sims in good moods doing these activities with their loved ones do so in a less mean way than grouchy sims in bad moods or engaging with relative strangers, but I'm probably projecting. When Valentine Hart hurls balls at his kids' heads I can almost hear him encouraging them to stand up to the ball, not to be afraid of it, that he knows they can catch it and nobody's going to go easy on them on the playing field. Ninety per cent of this game occurs inside the player's head anyway.

@Peni Griffin I've been seeing this a lot in my game today, I have a very sloppy sim who constantly clears up dirty dishes and coffee mugs. Then I remembered that once he had a lodger (room-mate) at his apartment, who was very addicted to the coffee machine, and so a few times I directed him to clear up the mugs and plates the lodger left around, as everyone was complaining about the stink. Since then he's autonomously cleared up, even though if I direct him, he complains at me. I agree that most of this game happens in the player's head, but maybe some of it is in the sims' heads- they imagine they hear me yelling at them through the screen, and clear up before I do!