Our attitude is our choice is a loud theme in all of his writings. Another, not so obvious, theme is focus more on yourself; your attitude, your choices, your performance. He emphasizes that when you focus on what you do, and not the others around you, it will make you happier at work. I would go one step further and say that when you focus on yourself and on being your best it will not only make you happier it will get you further in your career. Don't worry about others around you not doing their best. Make sure you are always doing your best. Don't try to top someone else's performance. Be the best you can be. Success may come from beating them, but excellence comes from being your best.
If I ran a 5k with my 6 year old son, I would certainly beat him. Success, yeah, I won!!!! Not really. I wouldn't have pushed myself to do my best. I wouldn't have set a PB. I would have performed less than average.
When you apply this to your career it can be amazingly eye opening. I will never forget my personal end of the year job review a few years back. I had really thought that I performed amazingly well and was very disappointed to only have a "good" rating from my boss. He could see that I wasn't taking it well and explained, "Thompson, you can't compare yourself to other people in your role. You may have outperformed them, but that is not the bar you should be measuring yourself against. You have to look at your individual performance and what you are capable of doing." I hate to say that he was right. I can't say that I will never coast again (OK, those who know me know coasting isn't in my DNA and I sure hope my boss isn't reading this), but I will never compare my performance to that of others. I am committed to doing my best.
Jon Gordon also has a pretty good newsletter, and unlike some other sites, he does not bombard you with a ton of junk mail. Here is a link to see a sample and register. http://www.jongordon.com/newsletter-112910-happinessatwork.html