I've heard about this thing called a 'buy back' drink where they give you one free if you tip really well a few times; however, if you do get one, are you supposed to tip for this too? And if so, how much?
Also, when I was in Canada, I got a glass of wine, I paid, including tip. And then afterwards the waitress came over with a glass of water for me. I was very grateful because I always like water with my wine - however I didn't know if I should've tipped again - so I didn't. What should I have done?!