So, everyone's got an identity. What you think you are, what you identify with, how you'd describe yourself.
This identity thing is a big deal in terms of how you see the world. If there's a clash between the world and your identity, you'll probably favor your identity over the world.
That's... not good, but it's almost everyone. A few people seem to dissolve their identity, or base it around a rather robust principle (like truth, in the pure abstract unfiltered form) - but that's incredibly rare.
So okay, you've got an identity, it affects how you react to the world, and if the world and your identity comes into conflict, your identity is probably going to win. That's not necessarily a good thing, but it's how things are.
Given that, it's really important to not have an "oppositional identity" - that's where you define a big part of who you are as what you're against.
Link: http://ebooks.adelaide.edu.au/j/james/william/talks/chapter8.html (found it via http://everydaysystems.com/)
All our life, so far as it has definite form, is but a mass of habits,— practical, emotional, and intellectual,— systematically organized for our weal or woe, and bearing us irresistibly toward our destiny, whatever the latter may be.
Habit is thus a second nature, or rather, as the Duke of Wellington said, it is ‘ten times nature,’