I have been thinking about group dynamics, and it seems to me that it can help explain behavior as much as personality types do.
Consider the following situation:
Say we have a group of college/high-school age friends that hang out regularly. One, say Brandon, is more fanciful in speech than the rest(or insert other oddness here). One person, say Jon, mocks Brandon for it, though not maliciously. Brandon shrugs this off since Jon is a good friend. Others in the group (also without malicious intent) also mock Brandon for fanciful speech. Brandon comes to identify himself as the person who uses fanciful speech in the group. He also has a subtle feeling that it is not a trait that is well liked.
The group of friends move-on, and go their separate ways. Brandon comes to meet another group of friends, all quite fanciful in speech, so he fits right in in this setting. However, their group is mocked by outsiders in very malicious tones. There is often physical bullying involved. Denial of access to certain things and ostracizing of the whole group that uses fanciful speech. Here Brandon takes a stand: "There is nothing wrong with fanciful speech. It is just a preference. These bullies are evil."
He returns to his old home town to hang-out with his old friends. They start mocking him for his fanciful speech as they used to (again without malicious intent), but this time he blows-up at them. "You guys are bullies-- evil people. You are not my friends. You have never been my friends. You've always mocked me for this." The friends believe "Brandon has changed. He's gone psycho." Friendships are lost.
I think there are many circumstances that arise simply out of the mindsets that people are "primed" to at the inception of social interactions. The behavior is as much a result of this "priming" as it is the "innate" nature of the individuals involved.