And now you're 22! Yippee! Happy birthday, Shenmue~!
Regarding insults in Van's culture: his people live under a very strict hierarchy and class system, in which whoever is above or below you in station is painfully relevant to your standing as an individual. His race has also conquered many planets in the past, and a distinct feeling of superiority over the conquered may be assumed, as well. As a result, praise and insults fall under several categories, with insults and self-deprecating references taking up a bulk of the language's honorifics and phrases.
Basically, you can compliment, kiss up to, affirm, or just add respectful honorifics to someone's name or actions about 10-20 different ways. You can criticize, scathingly insult, negate, or add less-than-desirable honorific descriptors to someone's name and actions in twice that many ways. Typically, negative comments are not said in front of a superior's face, and tend to reflect a deep-seated cultural distaste for the rigidity of the class system.
Apologetic statements and self-deprecating insults, however, are the most common of these sorts of expressions. There are plenty of ways to apologize for one's mistakes, at varying levels of humility. There are plenty more statements one can use to casually and insultingly refer to oneself, although these sorts of statements are really only common amongst the down-trod lower classes, anyone that spends most of their time apologizing (and is aware of it), or anyone who just sees themselves as less-than perfect and wants to make light of it.
And, what is insulting when said one way can be barely offensive in different context. Referring to people as "moron" isn't always a huge insult, if relations are taken to account.
Van can refer to Mar as "Mar-zhen" (Mar-moron) to his face, because (A) Mar is a powerful Oligarch way above Van's perceived station, (B) Van is an outlaw, and any respect he commands amongst pirates isn't recognized by the government, and (C) it's pretty much expected that Van would hate Mar, and Van insulting Mar is actually somewhat pointless. Space pirates are typically a barely organized group, and while the Federation/Oligarchy isn't much better off, Mar at least has plenty of political control over them... and his own private Armada.
Regarding "moron", again, there are much more demeaning ways "zhen" can be added to a word or statement available. And, it is typically a rather serious put-down. Van and Mar just have a "special" relationship in this sense.
