Sorry if there was already a thread about it but I'd enjoy seeing some more viewpoints on this. :3
Basically what the title says, what are the best things they improved upon since Oblivion or Morrowind?
I personally enjoy the fact that the guards allover the kingdom don't have a psychic connection about when and where you stole a spoon, then having to pay with your blood.
It's also awesome that whenever your stupid companion jumps in front of your sword while you two are trying to kill enemies, you don't get charged with a crime and they don't start attacking you in response.
I like the way NPSs react on your doings. For example when I bump into a bookshelf, some-one told me to watch out where I'm going. Or when I was over encumbered and was using Whirlwind-shout to reach Markarth faster, a guard came to me and told me to stop shouting, it made people nervous.