In a bar last night, I caught a server on an off night. The table next to mine walked out before they were even served, tired of waiting for a beer, and our table had a lot of trouble getting the check when it was time to leave. There may be no more frustrating feeling than trying to make eye contact with a server, who seems to look everywhere but your table. That said, I had a beer when I needed it and was content to wait because I was catching up with friends I hadn't seen in some time.
I left a fine tip, but it got me to thinking: When is it OK to leave a really bad tip?