Great idea for a thread!

When eating at a restaurant that you think you might visit again make a point of speaking to the manager or owner (compliments are nice but even just "saying hello" is good). Over the years I have received all sorts of nice "extras" from complimentary drinks to dessert to wonderful dishes (tapas portion) made esp for me and whomever I am with "to taste", to gift certificates at Xmas time as a "thank you for being our customer" or in the case of Asian restaurants as Chinese New Year gift certificates "to bring the restaurant good luck" ( by giving something away I was told they will receive good luck in business for the coming year).

And even without the "extras" it is always nice to go to a restaurant where you are greeted warmly and made to feel truly welcomed. And some times you will meet the most interesting people that way.