It seems its not just about playing poker - alongside the game is an unwritten law of poker etiquette that players should abide by. Its a long list, bound by years of tradition so here's a few

For example - Code of poker conduct number one - especially at low limit tables - is never show your cards to another player who's not in the hand

I once sat across from a player while holding pocket queens and saw my opponent lift his cards up to his eyeballs just to show the other half of the table what he had during the betting rounds.

He hit quad nines on the flop (a nearly unbeatable hand), so he was just showing off. I went on to pay him off with my overpair to what felt like an innocent board of two nines and a seven.

Next rule - which even has its own cliche is that of "show one, show all" - in other words, don't just show the player next to you your hand - at this point, the dealer will usually turn the cards over so everyone can see them

Third: Never act out of turn - however excited or depressed you are with your hand. Here's why:

It gives your intentions to the skipped player (information the rest of the table didn't have access to), while also rudely squashing his or her ability to make a clean play.

An out-of-turn fold also hurts the rest of the table since it gives a skipped player the opportunity to add value to a marginal hand if table position becomes a factor.

The nice thing about all this though is that if you're new to the table, you'll learn quick - and if in doubt, just ask the dealer

Article: Manners count --- even in poker