I have a relatively simple question that will sound foolish to experienced diners: in an upscale restaurant with a prix fixe tasting menu that states "Service Included" on the menu, what do you do when you meal is over? Sign your check and leave? Does anyone leave an additional gratuity, or does the waitstaff not count on receiving tips above and beyond the included amount?

Being an American (where there are tip jars at McDonald's) and being raised by my mother to never leave less than 15% for table service no matter how bad the service is, I would just feel a little awkward being waited on by 5-6 staff for 3+ hours and just signing the check.

Thanks in advance.