One of the problems people might have understanding a new concept is because they may have preconceived notions, and anything that challenges these notions may be immediately refuted. It's all mental, if you come with a negative atittude towards something it may be no use to learn about it because your mind has already been set up to disbelieve it and will only focus on digging for clues that refute the new idea and approve the old imprinted ones.
Mike