Outliers

"The striking thing about Ericsson's study is that he
and his colleagues couldn't find any "naturals," musicians
who floated effortlessly to the top while practicing a fraction
of the time their peers did. Nor could they find any
"grinds," people who worked harder than everyone else, yet
just didn't have what it takes to break the top ranks. Their
research suggests that once a musician has enough ability
to get into a top music school, the thing that distinguishes
one performer from another is how hard he or she works.
That's it. And what's more, the people at the very top don't
work just harder or even much harder than everyone else.
They work much, much harder."

"The emerging picture from such studies is that ten
thousand hours of practice is required to achieve the level
of mastery associated with being a world-class expert—in
anything," writes the neurologist Daniel Levitin. "In
study after study, of composers, basketball players, fiction
writers, ice skaters, concert pianists, chess players, master
criminals, and what have you, this number comes up
again and again. Of course, this doesn't address why some
people get more out of their practice sessions than others
do. But no one has yet found a case in which true worldclass
expertise was accomplished in less time. It seems that
it takes the brain this long to assimilate all that it needs to
know to achieve true mastery."

"[...]achievement is less about talent than it is about opportunity."

From Malcolm Gladwell's book, Outliers.