The Sims 4 has no personality

Their social autonomy AI is basically not existent. That's also why the traits don't work. And they can't even do mean interactions autonomously. And mods can't fix this..since they are just rying  to ajust the emotion buffs but can't give them social autonomy AI.

I think they just need to completely overhaul the traits system as well as all the other systems they have implemented to have them work more cohesively together as well as have them matter much more.

The systems (sentiments, milestones, traits, lifestyles, etc.) as they currently are not inherently useless, but sometimes they overlap or don't make sense being together or even compete for attention. They really just need everything to work a lot better as I think if all these systems are properly implemented and combined Sims would feel a lot more lifelike.

I think the problem is that the foundation has too many problems. They've been building their house on sand this whole time so to speak. The Sims 4 was not well received on release, and had many features missing that previous games had at launch.

The best thing they did do with sims 4 is that it's more stable, seemingly build to handle plenty of expansions considering how previous sims games all would run worse the more expansions you had installed. 

With Sims 1 and 2 it's resolved with computers good enough, with Sims 3 it remains a problem. If sims 3 didn't crash all the time, slow down and have other performance problems, I would never have touched Sims 4 beyond it's base game and would have stuck with it. 

There's just no way to truly fix a broken foundation for a game like this, because the problems are at it's core. 

Yeah I agree with this, if Sims 3 ran as well as 1 and 2 do I would have never even gotten into the Sims 4. I played for about an hour when it first released and felt absolutely offended with what they gave us on launch. It was completely deplorable and an absolute joke. Later on I played a little more and more but always taking a few months to years off of playing.

However they honestly have done a good job in fixing most of its short comings, and as of now I haven't been able to put the game down since getting back into it last month after a few years break. 

They really just need to do something with the personality system as well as other systems that have been implemented so our Sims can feel more believable. I want my Sims to be smarter. I also want to add I feel the emotion system is a bit of a detriment to this game, it really shouldn't be so heavily focused on and if they were to remove it completely I would not miss it.

I agree. I have played Sims almost since launch. I started playing in 2001. The game has been with me for 25 years, and I constantly keep buying EPs and other packs for Sims 4, but I never really enjoy it as I used to, and the reason is exactly what you say: the Sims have no personality. You can make a bookworm sim, and they will go to the computer for fun instead of reading a book. You make a vegetarian sim, and they will autonomously pick a meat dish. You can make a sim who hates pranks and jokes, and they will autonomously tell jokes and do pranks. The only hint in the direction of their "personality" is a negative moodlet because, of course, the sim will hate having made a prank even if they autonomously did it... The whole traits/likes/dislikes stuff seems neat, but it really has no real effect on how the sim behaves. 

I know I'm the idiot here for still buying Sims4 EPs and other packs, but I just keep hoping things will get better. There have been very few packs that have actually brought something in terms of gameplay, for example snowy escape, cottage living and Business and Hobbies, and these are fun for as long as it takes you to explore the new mechanics/places. Once that is done, you are back to your useless sim. 

Having a family is a nightmare, because every sim has to be micro-managed or they will just be stuck in front of a computer/tv until they almost pee their pants, because even an active sim will not autonomously go for a run or exercise, they'll just sit in front of the tv and be mad about it...