1. Lessons should never be compartmentalized, because decompartmentalizing them always seems disruptive. Yet, progress cannot be achieved without continuous criticism and learning.
2. Everywhere in life, contradictions are inevitable, especially amidst human activity.
3. It's a meritocratic world. Contribute something valuable or perish.
4. You live a finite life. Therefore, self-interest is necessary at some, if not all points in life.
5. Sure, the world changes and so should practices. But the experience of elders counts.