In case you did not know. TIP means: to improve service. In Europe, restaurants advertise on their menus 15% service charge, so a small tip is optional. But in North America they make you aware that restaurant folks are underpaid, so we somehow have to make up for that problem with tips. Our daughter went to hotel dining school and said that if the service was not good, just do not tip. A small tip is OK for so-so service, but if service is beyond, then tip generously.