Everything about the game of poker is collecting information. You just made a big bet at a pot and you are thinking: Am I beat? Do I have him beat? I missed my draw, hopefully my bet will take care of it ? Should I show the bluff? Ninety-five percent of the time you shouldn't show your cards.
Showing your bluff in any situation will prove to your opponent that you are capable of making a play like that. Additionally, everyone at the table will respect your play more, if your move was in fact a good play. You never want to let anyone inside your head when it comes to poker strategy. Keep in mind, you show one player, you have to show them all.
There are situations where some feel that you should show your cards. You may have won the pot with a monster hand or a bluff, and showing your opponent this will strongly affect his game.
When should I show? Is the pot huge? Is your opponent in the think tank for an extremely long time to the point where it's visible what your move has just done to him? In this scenario, if he makes the right decision, showing will in fact make him stronger because he was right. Everyone loves when they are right. He'll feel better about himself and his play. Never make an opponent at your table feel better about his game.
However, if he is tilt-prone and makes the wrong decision, flip over those cards. He'll be beating himself up about it for the rest of the night. There's nothing more gratifying than taking a player out of the game either physically by busting him, or mentally by doing something like this.
Another time to show: Face it. Everyone steals … blinds. You have to. Have you been stealing enough to the point that it's getting truly entertaining to you? Did that J-2 represent the best hand you've had and still, nobody has called you? Well then, you've got a great table image, but at some point, you will get caught if they believe you really have nothing.
You want to represent every once in a while that you are stealing with a good hand, so showing your A-K or 6-6 might just keep your opponents convinced that you are just on a great card rush.
The downside: Of course, you are giving away information here about how you will raise with these hands, but for the price of plenty more blinds, it's a risk you should take.
One thing to always remember: It's all about table image. The decision on whether to show hands should be less about particular hands and more about overall table image and your long-term strategy at the tables