Tipping Story Problem...

The girls and I go to Ponderosa on Friday night. The deal there is that you wind your way up to a cash register to give your order and pay, receive a ticket for your food order and another for your beverage and sit down. The girls are both under three, so they get the buffet for free, but pay for their drinks. I use a coupon for my dinner order, so our total is $15.

We sit down, and the server is supposed to bring us our drinks and my food order, but take 15 minutes to find us. After that the service is average to good, including refills, and my food being brought out promptly.

The tip should be...