Originally Posted by
swag
My rule of thumb is that if I'm using a coupon, groupon, etc, I'll tip on the full pre-discount amount. But if the restaurant is offering lower prices or specials, like during happy hour, then I'll tip on the actual bill.
I'll sometimes round up on drinks (not food) if the prices are really cheap, e.g., if it's dollar draft night, I will tip more than 15-20 cents per round.
I feel the same way. If I have a coupon, I tip on the amount before the discount, but it would never occur to me to tip more during happy hour, for a special dish of the day, or for a pre-theater menu as these are presumably times when the restaurant would otherwise have few customers to tip the waitstaff.