I'm seeing a lot of sims walking through walls lately. Its like they MUST find the most narrow place to walk by something, like another sim, instead of walking where there is more room. They keep walking through furniture and stuff too.
For eating, I never set the table. I've been so fed up of them wasting time. I ask them to grab leftovers then go watch cooking show (unless its maxed, then they can do whatever). So they got the food, then sat down at the dining table, then grabbed their meal, walked over to the sofa to turn on the telly. I wanted to get rid of that middle "station", so now I have the dining table placed at the back of the sofa, with the chairs facing the tv. Or I just sell off the dining table alltogether. If they're being dumb, they can't have nice stuff, even though it feels like I'm punishing my little people for something they can't help doing.
Some times they will go sit on a bed to eat, if another sim is in that room. I just can't get rid of their beds as well. Its more a problem in larger houses, of course.