For one thing, it's naive. Any attempt to assert that "X is entirely my fault" is naive. How can you eliminate the impact of your circumstances? For instance, you're here in 2012, working in San Francisco - one of the most exciting times/places ever.
For another, it's happiness-centric, which is boring. I basically don't trust anyone who says that the point of their life is "happiness." Frankly, the idea creeps me out. Sure, happiness is nice. So are transcendance, admiration, comfort, contentment. I also like nostalgia, gloom, longing, ... Life is not some simple game where you can just declare yourself the winner.
Finally, it's positivity-centric. One of my least favorite things about the ethos of the bay area is its inability to bluntly deal with negative feelings/ideas. Everything's always supposed to be getting better all the time - feeling better, running faster, etc. It's boring and unrealistic.
I worry about what will happen to someone who has this sort of mindset when they are older - when the illusion that they are in control of their happiness begins to fade - what happens when calamity strikes.
The universe is very old and you are a tiny speck in it. Concentrating on yourself in this way is like a dog chasing its own tail.
PS - God, and it's so arrogant. I hate this type of "I've figured it out! Eureka!" post/sentiment/essay. It's like a Buddhist claiming that they've been enlightened. It just smacks of self-aggrandizement and insecurity. Blech.