"If you're suddenly doing something you don't want to do for four years, just so you've got something to fall back on, by the time you come out you don't have that 16-year-old drive any more and you'll spend your life doing something you never wanted to do in the first place"

This quote by Ewan McGregor is a caution against settling for a profession course that you do not truly wish to pursue. He is suggesting that if you select a career path that you do not have a passion for, you will ultimately lose the drive and ambition that you had when you were 16 years old. This implies that you will invest the rest of your life doing something that you never wished to do in the top place. He is recommending that it is much better to pursue something that you are passionate about, even if it is a danger, instead of opting for something that you do not wish to do. This quote is a pointer to take risks and follow your dreams, rather than settling for something that you don't really desire.