Sharking is bad, but it is good to discuss in the open
You know, if your opponent respects your game then watching his game can have an influence. If you don't watch while he or she is shooting, then that can be sharking - intentional or unintentional. So this leads to a sticky situation. This comes up in 8 ball often. Let's say your opponent is considering which ball to pocket, and you are watching. Let's say you're an advanced player who knows how to use body language regarding which ball or even which half of the table you appear to be focused upon. I know that with a good percentage of weaker players, I can face my eyes, face, body, or even the shape of my overall presence (including my cue), to indicate which shot is best. Ok, let's say that this is sharking just for the sake of the argument. What are you going to do, look at a ball that if he pockets it will bump your ball into a cluster or ruin your pattern? There are many things that I know to do that will influence my opponent that I refuse to use because they are sharking. If the opponent is setting up for the shot that I want him to select, then is going to turn to consider the shot disadvantageous to me, I could preemptively turn my attention that way then turn back as if I were considering it, then reconsider and turn back. Often the weaker opponent mimics the behavior and chooses the shot advantageous to me. I know this works, but I will not do it because it is sharking - it is actively moving around to influence the opponent. Simply watching passively is not. Sharking can be subtle. But if you don't shark then your game will be stronger and you will enjoy it more. If your sharking fails then when you get back to the table you will be aware of your weakness.
