You should always assume good faith. "Assume good faith" is a fundamental principle on any wiki project. In allowing anyone to edit, we must assume that most people who work on the project are trying to help it, not hurt it. If this weren't true, open-source projects like those found on Wikia would be doomed from the beginning. When you can reasonably assume that a mistake someone made was a well-intentioned attempt to further the goals of the project, correct it without criticizing. When you disagree with someone, remember that they probably believe that they are helping the project. Consider using talk pages to explain yourself, and give others the opportunity to do the same. This can avoid misunderstandings and prevent problems from escalating.