Lesson 2: Not all parts of your life will be ideal at all times.
Lesson 3: Any complex system that uses human beings as input will be non-ideal for many (if not most) of those people.
Lesson 4: Humanity's sacred institutions are (contrary to the way they're marketed) full of frustrating inefficiencies and design flaws.
You're frustrated because you'd like to be constantly challenged by just the right amount so that you can learn and reach your potential. Consider the video game: each new level is designed to push your skills just the exact amount. Life (and human institutions) are not so well designed.
There's a reason that the book Ender's Game is so engaging: it's wish fulfillment. We all wish that we could go to a school that provided exactly the opportunities that would make us the people we want to be. But such a school doesn't exist.
(Oh, and on a practical note: if a subject seems dull, then hit the library/web and look for other textbooks on the same subject. A book that presents things the way you'd like to see them can make all the difference.)