Being friendly is great however, when someone comes in at lunch just to pick up something quick, don't follow them to the door talking if you are slow....makes me dread going in at lunch knowing I'll probably be late getting back to work.
Don't offer your classes just during the day because many of us have to work too. I'd really like to take an early bird class sometime because the rest of the day is so hectic it would be nice to be creative to start off with.