From Anna

I once worked in a bar that had a customer who would snap his fingers and whistle to get the attention of the bartenders.

The first time I was behind the bar and he did it to me, I ignored several attempts before just happening to be in the area to get his drink.

The second time, I realized that ignoring him was too subtle a clue for him to grasp.

I walked up to him, looked him in the eye and said, "Let's make a deal: You don't call me like a dog, and I won't piss on your leg. Got it?"

Next time, when he politely raised a querying  finger, I nodded and immediately approached.

"See?" I smiled, "you get service faster this way."

He made a sheepish grumble into his cup and behaved himself for the rest of the night.

--Anna