I haven't banned it long term but have short term, and it's.... surprise surprise, the GRILL! I have had two sims now almost burn the house down or burn themselves alive (that one was over to visit and not in my control, the other who almost burnt the house down was in my household but snuck by me while I was tending to a toddler). All because they had zero cooking skill and instead of waiting two seconds for whoever was at the fridge to move, they autonomously decide that it's a good idea to cook something on the grill with no cooking skill! But alas, I like burgers and steaks (and meat in general), and like for my sims to eat it too, and for some reason hardly any of the stove meals have meat in them, so I can't actually ban the grill (even though I want to).
Things that I did end up banning in my first save file, which have also never made their way into my new save file, are the gaming rig as mentioned (it's all been said well, no further explanation needed), and the cupcake factory. When my sims would get hungry instead of going to get leftovers made by the Level 10 cook in the house, they'd decide they were just going to make a batch of cupcakes instead. Then I'd have to cancel, only for it to be too late and I'd have to throw away the cupcakes (I prefer my sims to eat more nutrionally as a whole and not gain 400 lbs). In my first save file I also ended up having to ban the observatory, because everyone in the house seemed obsessed with it, to the point where they'd ignore what I told them to do. I do have one in my current save, but it is kept at the very back edge of the lot, and now these sims hardly ever try to use it (not sure if it was patched or if it's a matter of distance).
