The most sharkable player I ever saw was a guy who was in our house league for a while. If he was down on a shot and somebody three tables away -- yes, really, 35 feet away -- was moving to their next shot, he would grumble and get up. He wasn't in league long.
On the other hand -- from my August 2000 column in Billiards Digest
I saw the other extreme in a practice session of Nick Varner's. Nick was attempting to run as many balls as possible in one pocket (that's another challenge you might try for focused practice). He had been shooting sets of this for a few hours on the table right in the middle of the pool room, which was chosen because it had the best cloth, although everyone who came in would have to pass it on the way back to the counter.
Two policemen — levis, blue windbreakers with "POLICE" on the back, guns strapped to their hips — came in the front door and proceeded by the table and back to the rear of the building to round up a teenager who hadn't really done anything but wasn't where he was supposed to be. I was watching as they got the kid into an arm-lock to move him away from his friends by the pin ball machines.
Nick continued to play. As the gendarmes moved towards the door, they stopped right by Nick's table to put the cuffs on for a more comfortable stroll to the car. Nick continued to play. He never mentioned the incident, and I believe he did not even notice that it was going on.