Last night we went to a local restaurant, only second time being there. Food came quick, was okay at best, but the service was shit. It started out good, but she never stopped by to check on us for refills, and after dropping off the food only once asked if we were done (my wife was in the restroom with the kids so I said no, probably another 10 minutes). It was 40 minutes before anybody came by again, because people started coming in for new tables and they got "busy".
When she finally stopped by again she was in a rush, and obviously wanted us out of there. Our kids' meals came with an ice cream or something, she didn't offer or mention it, and I wasn't going to sit around there anymore, so figured a $0 tip would balance out the loss of a dollar or so worth of ice cream.
If she had checked on us only once to offer a refill or hadn't forgotten that last bit, she'd have gotten a tip.