Even though he’s not completely Thomistic in his treatment of the virtues, C.S. Lewis brilliantly explains in chapter 2 of Mere Christianity the difference between vanity and pride:
That is why vanity, though it is the sort of pride which shows most on the surface, is really the least bad and most pardonable sort. The vain person wants praise, applause, admiration, too much and is always angling for it. It is a fault, but a childlike and even (in an odd way) a humble fault. It shows that you are not yet completely contented with your own admiration. You value other people enough to want them to look at you. You are, in fact, still human. The real black, diabolical Pride comes when you look down on others so much that you do not care what they think of you.
So, CS Lewis basically holds that vanity is caring too much what people think of you; pride too little. I often wonder, then: How does one balance the virtues of indomitability and meekness? How does one balance magnanimity and humility? One of the keys to all of these balances is to simply admit to yourself that you will never please all of your enemies. Therefore, go ahead and make resolutions without care of others. You will never satisfy everyone, so just follow Jesus Christ.
In one of my favorite sections of Introduction to the Devout Life by St. Francis De Sales, the great Doctor of the Church shows that you must maintain your personality and Christian resolutions, regardless of what your enemies (or friends) say about how you live. The saint demonstrates numerous humorous balances: If you go about in a carefree manner, you’ll be accused of living in dissipation by your onlookers; if you live in moderation, you’ll be accused of dullness. If you spend a long time in confession, your enemies will say you have major mortal sins; if you spend only a little time in confession, they will say you’re not confessing everything!
In a section titled, “We must not trifle with the words of worldly wisdom,” St. Francis De Sales writes a timeless explanation of the foibles of human nature:
It is not possible to satisfy the world’s unreasonable demands: “John the Baptist came neither eating bread nor drinking wine; and ye say he hath a devil. The Son of Man is come eating and drinking, and ye say, Behold a gluttonous man, and a winebibber, the friend of publicans and sinners.”
Even so, my child, if we give in to the world, and laugh, dance, and play as it does, it will affect to be scandalized; if we refuse to do so, it will accuse us of being hypocritical or morbid. If we adorn ourselves after its fashion, it will put some evil construction on what we do; if we go in plain attire, it will accuse us of meanness; our cheerfulness will be called dissipation; our mortification dullness; and ever casting its evil eye upon us, nothing we can do will please it. It exaggerates our failings, and publishes them abroad as sins; it represents our venial sins as mortal, and our sins of infirmity as malicious. St. Paul says that charity is kind… but the world is unkind; charity thinks no evil… but the world thinks evil of every one, and if it cannot find fault with our actions, it is sure at least to impute bad motives to them,–whether the sheep be black or white, horned or no, the wolf will devour them if he can.
Do what we will, the world must wage war upon us. If we spend any length of time in confession, it will speculate on what we have so much to say about! if we are brief, it will suggest that we are keeping back something! It spies out our every act, and at the most trifling angry word, sets us down as intolerable. Attention to business is avarice, meekness mere silliness; whereas the wrath of worldly people is to be reckoned as generosity, their avarice, economy, their mean deeds, honorable. There are always spiders at hand to spoil the honey-bee’s comb. Let us leave the blind world to make as much noise as it may, like a bat annoying the songbirds of day. Let us be firm in our ways, unchangeable in our resolutions, and perseverance will be the test of our self-surrender to God, and our deliberate choice of the devout life.
—St. Francis De Sales, Introduction to the Devout Life, Part IV, ch. 1.