Something that is really counterproductive in many Open Source communities are people who are so rabidly fanatical about one line of thinking that they try to pressure everyone into their line of thinking. One long standing example of this is the whole FLOSS vs. FOSS concept. Some outspoken individuals try to lash out at all people who don't take their view on Free and Libre Open Source Software...that is, software that is Open Source, Free, and Libre (aka without proprietary parts included). It's really sad because this shouldn't be an issue in Open Source and Linux communities but it often is.
Linux Reviews, News and HowTo Guides