I made a small apartment in my store. It came in handy when my Sim needed to stay late. Her daughter would come by after school, do her homework, then hang out dancing in the kitchen while Mom baked the next day's pastries and prepared a small meal for her hungry offspring. Then they'd watch a little TV and chat before going to sleep in the double bed.
Next morning, the store would open at 7, and daughter would hang out in the store chatting up customers before heading off to school.
Play times like these really warm and fill my heart.
Side note: I really wish we had the ability to stagger employees. I have noticed that if you play as a household than the store owner's, and take them to the store, the store will open and employees show up and sell your goods, without needing to be paid or having to leave.