Politics, Sexuality etc - these can easily escalate into fights, so try to avoid any controversial subject. An admin can and will ask for these conversations to be moved to PM so that the main atmosphere of chat is not overcome.
Vulgar language is requested to be avoided. An occasional slip of the tongue is okay, but severe swears are not allowed. An asterisk should always be used. If you persist after being asked to stop, you will be kicked, and if you persist further given a cool off block.