Sim just stands there

[MomOfMany]

I don't know why but it seems like every game I play I have this problem were I tell my sim to do something and he/she just stands there for like 30 minutes to an hour sim time. It's really frustrating. Does anyone know the cause of this? It seems most often it happens when I cancel an action and send him/her to do something else. I just want to if there is a fix to this?

[Hechicera]

I'm sorry. I see this too sometimes and it is frustrating. With mine they are often in the kitchen, holding food, with a blank queue of actions. It is like they were eating and ... forgot! I think they stay that way until I notice.

I have no idea what is causing it. Some threads on toddlers on the official boards mention it as happening/worse after the update. I only restarted playing, happily for me two days before the toddler patch, so I can't tell you if it really is new from that. maybe someone else can. I wouldn't trust if I saw it from when I played before as my computer had gotten too slow, so much of my freezing my computer. I do have a nice new one though now, which is why I am back. That is only relevant as I am pretty sure any lag/freezes aren't my computer now, and this doesn't feel like the old freezes. And, I do see it also on my fresh install, no mods new family, no bloat game. But I also don't know why, sorry.

[MarianT]

I've had one sim do this in a fairly long-standing file (5 generations). Typing M as if I were going to send her somewhere and then canceling the travel command seems to get her back to taking a shower or whatever I had in her queue.

[Playalot]

Sometimes hitting the pause button and letting the emotion change or an in-game notification appear helps too.

[Kellven]

DO NOT USE THIS MOD UNLESS IT GETS UPDATED!
Simulation Lag Fix
http://www.modthesims.info/download.php?t=585420

Also there was a thread here about game time flow issues.

I have not seen the code responsible, do not work on/mod this game, or any other such; this is purely my opinion on what is causing the issues, and we all know what opinion is worth.

From what I understand, what's been happening is that the game was originally designed to process "all the action" going on in the world in a single "thread"(programming term).

<Technical computer junk>
 Contemporary computers are really many(almost always 4) computers basically manufactured together, with some coordination between them. To use more than one at a time, you need to use "threading", which is a very very complicated, migraine inducing, clunky, obnoxious programming task.  Threading allows multiple "streams" of commands to work simultaneously, saving time. Managing threading itself costs time, so when you're designing an application that uses it, you need to measure and balance how many "streams" you have going, and how much work you put on each one, rather than just tossing out new ones constantly, or you end up losing time.

  I believe that when the base game was designed, the time balance came down for putting all the "action" work into a single thread, along with the autonomy(AI). Since then, however, there have been years of additions/expansions/whatnot piled on each other, and it all ends up being processed by the same single thread, a design that was never reevaluated after the base game launch.

  What I've been seeing since the todler/vampire patch is that even on my year old gaming rig, there's just way too much work being dumped into that single stream for even my processors to possibly work through in real time.  The result is the same kind of lagfest executing actions we had in S3, along with the (for me) recent time weirdness(probably also dumped in the same thread).  I suspect the issue that broke things for me was vampires having a massive block of condition checking on actions.
<End Technical computer junk>

  If I'm correct, and it is an overloaded thread issue causing the action/mood processing lag, and the game time processing weirdness, the correct solution unfortunately, is for EA to task their resident threading expert(not a clueless unpaid intern) on overhauling the S4 project as it stands now, with an eye for future code bloat. Good luck convincing EA to do that.
  Fortunately, the code governing that particular problem is apparently exposed for modding; so in theory, someone can maintain another "unofficial fix" until/unless a miracle happens, and EA does the right thing.

[Playalot]

As a friend of the modder that made the Simulation Mod I can inform you that the python files that were in the code that were used to make this mod have been removed by Maxis. As such the modder has no plans at present to work on any other simulation lag fixes.

There is already a post about this mod here, where I have informed the community about the status of this mod.

While theories and modders ideas as to what exactly is causing the lag is interesting it is (often well based) speculation really and there is little that we as game-players can do. 
What I do know is that there are developers who are continually looking at how to improve the games performance, I guess we have to hope that they can continue to improve the optimization, especially as we have 19 pieces of DLC and more to come.