We were sharing a section and I went to a table that I did not know had just had their drinks refilled, as I walked off I heard the woman say, "They always try to hear what I am talking about, that's why I never leave a tip when they come over more than three times". My co-worker who handed them the check at the end of the meal, had earlier heard her say, "If I was in that section (pointing at a table where a birthday party was going with about 7 children) I wouldn't leave a tip over there, I haven't seen anyone who works here go by there in 15 minutes". We didn't put our instances of what we heard together until the end of the night.