Everybody has encountered this person, the person who refuses to admit that they are wrong, and they exist on both ends of the political spectrum.
This person usually contradicts themselves at least 5 times during the "debate" and maybe a few times in appearance alone. For instance, a girl tried to get me to sign a peta protest against KFC, and as she was telling me about how badly they treated animals (i listened because she was hot), I noticed that she was wearing leather sandals, and had a leather handbag. I proceed to point these hypocrisies out, and go on to further explain that it is U.S. law that all chickens be killed by either an electric shock (which if you're like me, you've been electrocuted before and know that while being electrocuted you don't feel a thing, its after that hurts) or electrically shocked unconscious in order to be beheaded, which are two rather human, and painless ways to die. She got pissed and rambled on about fascist pig or something, and i mentioned that her rambling had nothing to do with my point, or the point she was protesting, so she left in a huff. Clearly i won that argument, but she'll probably never admit it.
There favorite tactics are the use of circular logic, disregarding your established statements and facts that don't fit into their argument, but are very relevant. I have encountered people like that in my short time on this site, and many a time in real life, and not to be sexist, but most of them are young women in their teens to late 20's who haven't experienced real life yet and are still coddled by their parents.
Ripping these kinds of people new butt holes is my schadenfreude (German for guilty pleasure, or harming pleasure) because I really enjoy crushing their world views, but i also feel guilty having to do it to people who are so misinformed in their sheltered little lives, but I can handle that guilt, because hopefully they'll be better people because of me.