In poker, it's often required to keep quiet when you are not involved in the hand. Talking about your hand, commenting on other players' strategies, or giving advice during a showdown are all considered bad manners and may lead to penalties.

Show Respect: To keep a positive atmosphere at the poker table, always make a point to be polite and show respect towards others.

Don't berate the play of others or say what you would've done differently. ...
Don't go into a tirade after suffering a bad beat. ...
Don't be rude or mean.