http://www.doctorhurd.com/index.php/Daily-…-attitudes.html
Can’t the second attitude often lead people to strive for what is not possible for them? It’s not realistic for everyone to be a great singer, for instance.
You should live your life according to your nature. Your nature is a given, and from that, Objectivism teaches you to make the right choices.
That means that if you’re tone-deaf, you shouldn’t set out to be a singer, if you’re not athletically gifted (and I mean really gifted, not just a litle quicker than the other kids in your class), you shouldn’t set out to be a professional athlete.
You need to choose a profession which suits you, both because it is possible for you to practice it, and because you like it, and admire the people who are great at it. Then, you need to begin working towards your goal, and applying the attitude Dr. Hurd describes.
People are envious of people they would like to, or would have liked to become, not of others. For instance if a kid knew from age five that he’s tone-deaf (because he’s been told that, by the first person who made him do the whole do re mi thing), then he’s not going to set out to be a great musician, on any level (not even on an emotional one), and he’s not going to envy great musicians later on.
The problems begin when people are pushed to/choose do things they don’t have the capacity for. That is a wrong, immoral choice to make. That isn’t contained in Dr. Hurd’s short article, he addresses what comes after that: How to go about achieving your chosen goals when you’ve made them fully aware of your nature.
Another way to phrase this last paragraph is this: Dr. Hurd’s short article (basically one sentence) isn’t meant as the answer to life’s questions, the way the contents of a fortune cookie are. His advice pertains only to this one choice, which comes up once you’ve made other choices. (like the one I describe, which has plenty of pitfalls as well) Just because those pitfalls exist too, it doesn’t mean that this advice, when those pitfalls are avoided, is wrong. (when the previous pitfalls aren’t avoided, then this choice is a false one. One needs to go back and correct his previous errors first)
P.S.
If you like playing basketball, but are one of the 99% who don’t have the body it takes to be in the NBA, you can still strive to be the greatest athlete you can be, as a hobby, and you should still look at Michael Jordan and say: “Wow, what a great job he does. I’m going to strive for that, myself.”, meaning you’ll strive to be the greatest you can be, in those 3-4 practices/week you have time for, and the body you have.
One thing you shouldn’t do is sing, in the hearing-range of other humans, if you really can’t. 
Well put, Jake!