When you comment on my blog, don't lie. Take some care to check your facts, so you don't inadvertently look like a liar. Intellectual inquiry is difficult enough without having to constantly correct false statements obvious enough that a quick search on Google, Wikipedia, or talk.origins would discover the truth. If I decide you're lying, I'll ban you in a heartbeat.
I have some tolerance for misstatements of fact, but my tolerance varies with my mood and the tone of the comment. If your comment otherwise shows signs of intellectual honesty and truth-seeking, I'm much more likely to tolerate and simply correct a misstatement. If you're all mouth and trousers, if you open your comment with sweeping generalizations, and if you insult me personally or my readers' intelligence, I'm likely to ban on a first offense.
I have zero patience with cretinists, IDiots, Randians [Ayn, not James] and Libertarians. If you're advocating any of these ideas, check your facts extremely rigorously, because I'm already heavily biased — by virtue of long experience — in my opinion of your honesty and intellectual integrity.