Can I keep calling my parents hun?
Why call your family by something easier?
Because I don't want to say they're mean, but my life is mostly boring. And I think it is silly to call them by hard names.
It is rude to call people inappropriate names.  People might think you are weird if you keep doing it.
I don't care because I said so.
If they don't want to be called hun then you should respect that they dislike it. How would you like it if your parents named you something really bad and then got mad when you tried to change it later in life? It goes both ways!