When you have chosen a profession wich you do not like after 3-4 years, you naturally strived to hasten it towards retirement. And, this is the reason why men suffer from burn out while doing their jobs.
When you have chosen a profession for yourself, your favorite profession, which you can engage in "eternally", then you will behave as follows:
The paradox is this: the more you like what you do, the more time you're willing to spend on it, the less time you will be needed to master the skills. And therefore you spend less precious time, to succeed in life.
P.S. Thank you Kenny Wong for more accurate translation :)