I have a buddy that I wouldn't necessarily classify as a know-it-all but instead he lives in this delusional world where he's somehow refined in arts and culture. He talks like he is so worldly and philosophical but really he knows just a little bit and then just BS's the rest. Annoying as hell. We used to be the best of friends but now I can barely stand to hang out with him.
Example, taken from his Myspace page:
Well, humor is the very cornerstone of my personality. I thrive on social conviviality and my close circle of friends often say I'm "cultured." I'm extremely passionate about many things which makes it difficult for me to choose one activity to excel at. I'm a romantist, not in the sense that the modern definition would imply to people today, but a romantist in my ideals. A lot of my views on various subjects can be considered rather unorthodox, but just like anyone else, I have my reasons for adhering to them. As a ritual, I usually spend my twilight hours either reading grave subjects or listening to music in the dark as a form of meditation. Generally speaking, I'm humble and hospitable in character.
Talk about a load of crap.