There's been a brewing discussion going on, largely and appropriately in the high energy physics community, about string theory - does it actually have reasonably specific, testable predictions? If not, is it really science in the classic sense?
People can become incredibly personally vested in their ideas in science. In physics in particular there can be a tendency to assume (a) that you're right (duh!), (b) that your ideas have been arrived at by a careful intellectual process (duh! again), and (c) therefore anyone who disagrees with you is either ignorant, not very smart, or hasn't been thinking about things "the right way" (read: your way). Reminds me of Vizzini in The Princess Bride: "Ever hear of Plato? Aristotle? SOCRATES?! Morons." Prior to today, the best example of this attitude that I'd ever seen was at a talk given by a job candidate, who, when asked a very good question by one of my very respected colleagues (who happened to be on the search committee), began his response with "If you think about this a little, you'll see...." Nothing like implying that your potential future employer hasn't considered his question.
Now, though, I've got a new favorite example. From Lubos Motl's well known blog:
(UPDATE: Lubos has removed the page in question, so the link is now broken.)
(UPDATE II: Lubos has put the page back, re-edited, but the new version still conveys his clear view that only high energy theorists, and specifically string theorists, are actually doing science - the rest of us are just wankers, apparently.)
Sorry to say but this is the last well-known physics blog on this planet; all others blogs that claim to have something to do with science are just politically correct tools for crackpots to make their deep misunderstandings of the basics of modern physics ever more powerful and legitimized, and to destroy physics as such at a finite timescale.
Oooooookay. So, everyone else is a complete idiot. Got it. Might as well pack up my computer and quit now.