| rare case of being at a cheap breakfast place where 20% amounts to a pittance.| You shouldn't feel especially bad here. Breakfast joints are high volume quick turnaround places where the diners don't sit very long at all. I've known more than server that absolutely refused to get a job at a nicer place than the diner they were working at because the tips were more reliable and added up in the aggregate. they could always count on a solid breakfast rush that didn't vary from day to day. I usually default to 20% plus all change leading up to the next dollar in diner settings. There isn't really even an opportunity for a cheap breakfast place to give you "great" service, -they just have to not fuck it up by forgetting drinks or screwing up orders, etc.