1. Insults. Direct personal insult of another forum member (e.g., "You're an idiot.") and other name-calling. Why? Because this isn't junior school. People should be able to discuss or even dispute other people's posts without insulting people. You may dispute somebody's opinion but not attack or flame the person who stated it. There are a lot of other non-direct-personal insults that won't necessary get you banned instantly, but depending on the context/nature may lead to post editing, post deletion, reminders, thread-bans and section/whole forum exclusions. They include telling people to shut up, describing a member as an ignorant person (rather than ignorant about a particular topic), and being extremely or repeatedly rude or sarcastic. It's not your place to tell other users they are not welcome; if they follow the rules, they are welcome. Bottom line: don't try to tick off others and don't make discussions unnecessarily personal. If somebody else insults you, report their post; but don't respond in kind, their post does not give you a license to break the rules by returning their insults.