Comparing objects like cars, houses, clothes, and defining life according to those comparisons, instead of trying to discover the real reason for being alive.
Hope for the best, be prepared for the worse. Life is shocking, but you must never appear to be shocked. For no matter how bad it is it could be worse and no matter how good it is it could be better.
Christian love comes from the understanding that there is a unity of divine origins in oneself and in other people, and not only in people, but in all living things.
Learn from someone who has already been up there: no matter how unique you feel, there is always someone who has had the same dream before you and ended up leaving marks that can make your journey easier; places to hang the rope, trails, broken branches to make the walking easier. The climb is yours, so is the responsibility, but don't forget that the experience of others can help a lot.
I am sure it is one's duty as a teacher to try to show boys that no opinions, no tastes, no emotions are worth much unless they are one's own. I suffered acutely as a boy from the lack of being shown this.