I disagree slightly about working at a services company like McKinsey. Much of what he writes is true, of course. However, life is about trade-offs and one of the benefits of a services company is broad exposure to many clients facing many problems. This CAN prove valuable later, for those who wish to strike out on their own by building a useful product or service.
As an old service company employer adviced me, you should not waist more than 3 years at a service company , you never learn anything after that periode , you will just waist your time, better move on and build something useful in small companies.
If you end up starting a successful company this will in retrospect look like a brilliant move. But since most startups fail you may find that you are totally unhireable. There is a small window of opportunity to get these kind of companies on your CV and to learn from brilliant mentors. You can always go start a startup afterwards.
