Those who have betrayed you once will betray you countless times. You don't have to drink the entire ocean to realize it's salty. In the adult world, teaching someone for free is the beginning of making enemies. Never help someone climb out of the mud; you think you're helping them, but they might see it as showing off. Teaching others comes at a cost; being too proactive may lead to being treated cheaply. In the adult world, it's about filtering, not educating.