Although I am not a big Lewis fan, Knox Chamblin gives this great quote from Lewis in his (Chamblin's) book, Paul and the Self:
"Pride gets no pleasure out of having something, only out of having more of it than the next man. We say that people are proud of being rich, or clever, or good-looking, but they are not. [That is vanity.] They are proud of being richer, or cleverer, or better looking than others.... it is the comparison that makes you proud: the pleasure of being above the rest.... If I am a proud man, then, as long as there is one man in the whole world more powerful, or richer, or cleverer than I, he is my rival and my enemy." - Mere Christianity, p94.