Don't Think of an Elephant will completely change how you view politics and what anyone in politics says and how to interpret it.

Aristotle's Ethics helped me reconcile my desire to constantly strive to do more and what to make of it when it seems never-ending.

Plato's Republic goes deep into virtue in a way that somehow doesn't (and might need to) get explored more often today.

Excellent Sheep is the book that got me to read the above books in the first place.