Thanks for writing this. Circles of concern vs. influence, and optimism (as insightfully described in the article) are concepts that I have been practicing for years, attempting to teach to others, and have profoundly changed my life.

People reference 7 Habits so often but the things that are typically mentioned (the actual "Habits," per se) are not the parts that I found most life-altering. For me, it was the philosophy:

  -Character vs. personality
  -Abundance mentality
  -Responsibility = Response + Ability
  -Principles vs. values (and natural law) 

Actually this is the only summary I've found which hits on what I believe were the most important parts of the book: http://www.slideshare.net/shaludhamaniya/seven-habits-of-hig...