

Playing Poker, like all other games, require some form of code of conduct and manners where players and viewers alike must abide. The following are some no-nos in a Poker game:
Do not show your cards while a hand is on-going. In Poker rules, generally, this is not wrong although in some casinos, penalties apply. Etiquette will tell you that this is such a wrong move in a game of Poker. Why? This gives other players in the Poker game the chance to size up your card and totally ruin the chances of other players to win the pot prize. Apologize profusely if you have done this accidentally.
Do not overreact to the cards you receive while a game of Poker is still on progress. Reactions during the game of Poker usually tell other players the kind of cards you have. Poker manners - never slam your hand on the table, never let that jaw drop in awe or slouch in confidence in your chair. These actions, common in Poker, tell other players that you are going to hit. This can ruin the chances of you winning the pot.
Do not criticize the game play of your opponent. Poker games can be challenging sometimes but this does not grant you the right to verbally abuse other players. Do not be arrogant if you're a pro. Be patient all the time. Respond to comments humbly. Sarcasm in a game of Poker will not help you achieve anything good.
Do not project the blame on the dealer. In a Poker game, dealers do not control the kind of cards being dealt to players. Dealers are only doing their job. They do not exist in a Poker game to guarantee you lose or to make sure you get the losing cards. Be mature and responsible. Like you, anybody in the Poker game deserves respect.
Do not give advice to players while a game is in progress. In most Poker games, if you do this, you'd get fined. Poker players need to focus on their cards and on the strategy to use so the least they need is you blabbering on what to do. Otherwise, it's perfectly fine to talk about a hand if a Poker game is not yet in progress or if another player is talking about it.
In a game of Poker, you may sometimes speak in special circumstances like when a player called for a "raise" and nobody heard it. Dealers sometimes are too busy and bombarded with so much noise and this is a typical scenario. In Poker, you may stand as witness on behalf of the player and emphasize that the player indeed called for a raise.