I really enjoy insulting my family in my mind and then I laugh
How strange is that? Why would think stuff like that?
It makes me laugh.
What you decide to think about is totally up to you.  However, that sounds like an unhealthy thing to think about and you might want to consider therapy.  You shouldn't be thinking bad things about your family members all the time.
Ok wtf.
Yeah, I think if you are constantly putting down your family like that, you might accidentally let it out in real life. I believe then it's best to try to think of positively of them, because they are your family and don't deserve all of this putting down in your mind.