One of the most moronic things people have done to me intentionally and unintentionally is walk right next to the table in front of me while I am in mid stroke of a shot. A lot of pool players do that when they feel vulnerable during a game and they want to mess you up on purpose. They believe if they do this you will track them and not the ball you are shooting at. In some cases this may work on amateur player but an above average player will usually ignore it but this still does not make the situation any more fair or proper.
The correct pool etiquette is to be aware of your surroundings if you are in a pool hall, bar, or place that even has pool tables the best way to walk towards your objective but make sure the tables you walk past no one is shooting. If there is someone shooting and you need to walk in front of them pause and allow them to shoot, once they are done shooting quickly walk past and on the way back from your destination do the same tactic. If you need to walk behind someone shooting make sure you allow them enough room to pull back on their stroke. If there is not enough room please wait until they are done. If it is a player standing and looking at a table and blocking your path just use proper regular etiquette and use words such as “excuse me” and “pardon me” to get past, some people take non-manners to heart and it’s the basic thing most people should be doing anyways.