Well, for a profanity filter the answer is easy. I don't have one except around young kids and weirdly my aunt (who is also my godmother). I swear allll the time, on facebook, around family, with friends, to myself... It's just a habit by now, and not one I feel like trying to control.
As for insults and rudeness... I guess I have one, but I rarely ever need it. I generally don't like to talk mean about people, even when they aren't in the room. It gives me the sense that I'm trying to say I'm better than them, and if there's one train of thought I really hate, it's that you're "better" than someone for entirely petty reasons. We all make mistakes, we all have bad days, we all get mad. How childish and lame is it to believe you're a better person than someone because they did something dumb or got mad at someone on a bad day? Even people it would be normal to think of as bad people are almost always just products of their upbringing.
To me, everyone deserves to be treated with kindness and respect until they unequivocally prove they don't deserve it. Even if I don't like you, the worst I'll do is ignore you.
That's not to say I never insult people, but when I do I'm always joking.
Captcha: yellow-belly.
Reminds me to mention that some people who see someone refuse to be rude to others think they are cowards or weak. Meh. I'm not afraid to speak my mind, I just rarely think poorly of people. Although I make an exception on internet forums. Insults are just part of the culture here, and everyone is basically anonymous... so fuck all you guys.