Everyone has been asking this question lately, and it needs an answer. Well to start it off, many users have been getting in trouble for insults, but some question if their insults were ban worthy, and here is what I will tell you.
Insults are (and should) only considered insults when they personally attack a user. So, using myself as an example, let's say a user said "Bigez620 is a complete idiot, he makes moronic edits and is almost never around to help." -That is considered an insult, however, if you were to say "Bigez620 has been a bit inactive lately, I haven't seen many of his edits lately and there are some users who need his help when he isn't around." -That is not an insult. It's someone's point of view or opinion. People expressing their opinions sometimes comes off in a wrong way, but only should be looked down upon if it directly is too insult a user. Another example is this: "Bigez620 is a complete idiot for liking Ezekiel, he is the worst character, so I don't know why that loser would like Ezekiel." -Obviously an insult. If the user were to say: "I don't know why Bigez620 would like Ezekiel, I don't think he is a very good character." -That is not an insult, it's an opinion. So if some user expresses their opinion like that, please do not look down on them or act towards them in a shameful way.
Another subject insults are confused with is gossip. Everyone gossips, but it's not to be considered an insult if they do not say it directly to the user's face. If you were to say "I don't like Bigez620 much, he is sometimes rude to me." -It is in no way considered an insult, as it is someone's point of view. Or if you were to say "I don't think Bigez620 is a very nice user, he sometimes looks down upon me and shows little care for my help on the wiki." -This is also not considered an insult. Spreading lies is different though, as it could ruin a user's reputation. Example: "Bigez620 has called me a moron, and told me that I am a useless user on this wiki." -Unless you have pictures for proof, we cannot take you seriously.
If a user insults you in Private Message, it is a necessity that you show a screenshot of the insults to an admin, or it could go on for a while. But again, if you have no proof, we may take it as made up. Also, if you are constantly fighting with a user, you need to show us what they are saying to you, or we will take it as biased.