When your sim is going to class they carry their homework under their arm. When a sim gets a scholarship they do a little victory dance. When your sim eats too much quick meals, they get a moodlet that says something about not having a balanced diet. This moodlet disappears when your sim eats a healty meal.
When a fire breaks out on your homelot neighbours will come to the rescue and put out the fire. When you have cleaned up Sulani there is a chance that you will spot an albino dolphin.