It's a game and sims are not real. In some senses they act uncannily like humans, and I think this is what makes some of us "see" little pluses and minuses above real people's heads at times, and why at times I think about my "social bar" or "energy bar" - whether it is filled up or needs filling.
I would love to see sims that are more intelligent. I have seen that sims that reach a high level of competence in a certain subject will spontaneously use that skill sometimes. For example, a sim with high levels of mechanical ability repaired a broken computer without being told. These are things I find interesting and I love discovering them. I have been irritated at the selfishness of sims. If their fundamental needs are met - they are housed, have eaten, have enough sleep - then I feel they should take care of others, like babies, even if they haven't had enough "fun" or if their aspirations for bigger and better things have not been met. But the needs tend to be all equal in this respect. If they are lacking in some then they tend to lose their ability to take care of the slightest things.
I suspect that I am not the only one who likes to see them get into fights at times. This must be why the sim creators added greater "furiousness" to sims in one of the expansion packs. They stay mad longer and they fight more easily. Sometimes I just make it happen, like the time I had Don Lothario invite all of his conquests to his house for a party and then flirt with every one. By the end of the evening they all had slapped him silly. Loved it, loved it.
All this aside, I can walk away! I'm not addicted! Really!! heh...