You can sue you landlord as a result of the rude behavior of his superintendent as stated in your facts for your question but the chances of you prevailing in my opinion is pretty remote. The reason is that in this country one experiences many things, good and bad. For you to have a legal basis for bringing a lawsuit there must be some established cause of action as a matter for law and actual damages.Having hurt feelings alone as a result of someone saying that your are stupid and other insensitive things is simply not the basis for a lawsuit. The superintendent could claim what he said was his opinion and protected under our country's Constitution as free speech.Good luck.