Sure, introverts look mild-mannered, but don't be fooled. They can be as surly as the next guy--at least in their heads. They don't often say these things out loud because they don't feel like getting into it, but certain assumptions made about introverts really get on their nerves--and sometimes they get this kind of flak even from friends.
So if your introverted friend's face seems to suddenly freeze into a mask of benign tolerance, you might have hit a nerve.
With input from her readers, my friend and colleague Sophia Dembling, has put together the following list of some things that make introvert friends silently seethe. (If the shoe fits, take a peek at her blog, The Introvert's Corner on Psychology Today.)