[Florin_Andrei]

Could it be that the tendency to preserve the coherence of one's views goes beyond self-worth? E.g., most people, I think, would try to avoid holding in their minds ideas which don't agree with each other. So, if your previously acquired ideas are already leaning this way, they may tend to oppose new ideas that are leaning that way.

[Buttons840]

http://en.wikipedia.org/wiki/Cognitive_dissonance -- I believe this idea is called "cognitive dissonance", and has been demonstrated in some interesting studies.

As I read about it, I could remember several instances in my life where I have behaved exactly as described.