On the opposite side of the coin, I am not very appreciative when the people behind the counter are talking crap about their customers.
One time, I was in a sandwich shop, and I had a fairly specific special order and this guy is talking crap about all the customers in line, right in front of us... he's like, "bet you he won't even mention the special order stuff at the checkout."
Well, A) I can hear you, you dumbass; and B) Why are you asking the customer to tell the cashier what the order was, anyway? You guys are standing all of three feet away from each other, anyway...
I generally don't fill out those stupid feedback forms, but I did that time. The owner of the store called me up, took me to lunch, asked me to explain the circumstances and told me he had already fired half the crew (for various reasons), and then gave me coupons for free sandwiches.
That guy had all my respect, and his new employees were a heck of a lot better than the old crew were.