Generally I play by these rules :-1.
I never buy into a game with half the amount of chips hoping to hit big early then run (bank my winnings by doubling up)2.
Going all in is a hard one... as : a.
If my cards and position dictate I will go all in, more than once if needs be, but that is tactical.... b.
What is frowned on (and believe me I've played in a few live games where someone is doing it) is going all in because you lack the skill to play the hand properly (its the easy thing to do)3.
Abusing fellow players is also a two way street..... as: a.
A little sledging during a hand can tell you a lot about what type of hand your opponent is holding, though this is generally only done in live play. b.
Abusing / being rude / childish etc is just wrong and should come with an IP ban.4.
Showing your cards before the end of the game is one of the worst things you can do. When / if you ever get good enough to start to calculate outs and odds, being shown what a player is holding can massively throw the hand in your favour. (I cant understand why this option is even in this game, it serves no purpose other than to piss off the better players)
Off the top of my head that's what I can think off at the moment....
I've added an introduction to the forum so look it up if you want to know my background.