I've always pondered this--the idea of pride being one of the seven deadly sins. Pride in one's appearance, in one's intellectual acumen, in one's success--cannot be a bad thing, and I don't think this type of pride is what is being referred to. Or I think that one can distinguish between good pride (for example in the things above), and bad pride. Bad pride can be defined as an excess of pride, for example, pride in one's appearance can spill over into vanity and narcissism, pride in one's intellectual acumen can become an attitude of 'know-it-all' (besserwisser), and pride in one's success can become hubris. Hubris is excessive pride, foolish pride, arrogance. Hubris tells others that your worth, your intelligence, and your wellbeing are more important than theirs. Hubris is a feeling of superiority, of haughtiness, that leads you to treat others as less important than you. Carried to an extreme, it can lead to indifference to others (why should I care about them since they are not worthy of my attention) or to abuse of others (for the same reason--others are less or not important). Hubris leads people to selfishness because the only people who matter are themselves.
Christian literature is not always clear about such distinctions. For example, we are told 'not to hide our light under a bushel basket', which I interpret to mean that one should not hide one's God-given talents behind a sense of false humility. We should be proud of our talents and gifts; each of us has unique talents and gifts that should make us proud. So false humility is as bad as excessive pride in my book. If you hide your talents, you deprive the world of them, and they could have helped the world become a better place. If you are a good writer, artist, actress, and you touch people's lives because of these talents and have a sense of pride about that, that is a good thing, not a bad thing. The bad thing would be to pretend you were talentless in the name of humility. But excessive pride leads one to think that one's talents supersede those of others, that without you the world would fall apart, that you are what holds it all together. If we are talented and gifted, we come to a point when we realize that those talents and gifts were supported and nurtured by others, behind the scenes. We are born with talents and work hard at developing them, but our home/school environments also contribute to their development and evolution. In other words, we are part of a team of supporters--family, teachers, coaches--who nurture and challenge us to be better. Excessive pride leads us to believe that we have accomplished what we have accomplished, by ourselves. That leads us to conclude that we know best, that we do not really need others, and that leads to arrogance and indifference toward others.