I'm not always happy with where and how my sims eat, but I like that they do it differently, based on their person and the household. A sim can walk through many rooms in order to chat with another household member while eating. They often choose whether eating in the terrace or in dining room depending on where the other sims are. I hate it when they go to sit on a child's bed to eat+chat while child is actually trying to do homework. And even stupider it gets when they walk 3 floors and the sim they intended to chat with moved elsewhere before they got there...
About cleaning dishes, I see both. Someone mentioned in another thread that sims often need us to show them what to do to build their preferences, so maybe a sim who is directed to clean dishes a few times will do it automatically after a while?