When I did the Ironman last year, I told everyone about it: friends, family and co-workers. I did it on purpose. It was a risk I took, because would I have failed to prepare for the race or finish the race, everyone would have thought I'm a "looser" or "quitter". I used this fear as additional motivational fuel. Also, to my surprise, most people told me I'm an idiot for even attempting an Ironman and that I wouldn't be able to finish it. (Lesson learned: Culturally, here in Eastern Europe 'we' don't have the 'can do' attitude.) That was another huge boost, showing these people how limited their mindset is. It's kind of cheating, because you're using external factors to motivate you, but you need all the "help" to do extraordinary things.
Think of Ali when he was preparing for the Foreman fight --- he used an entire nation to motivate him for the Rumble in the Jungle. Whenever he got a chance, he went on TV and said he would destroy Foreman. He absolutely commited himself in front of the entire world and it worked for him. Foreman, on the other hand, was different, he was more introverted, and although he lost that fight, he was still a great boxer.
So, on a personal level, I strongly disagree with this article. I'd rather strive to be like Ali than accept some mediocre average.