I want to insult my family
What are you going to do to insult your family?
I might as well make my last statement at them by saying things that I've held in for many years.
I think it's important that you communicate with your family about what you've been holding in all this time.  However, you should do it in a respectful manner as people should respect their family.  You don't want to cause any issues, right?
True. When I confront them, I'll treat them in a polite manner.
Perhaps letting them know what is bothering you will help you form a better relationship in the long run.