If the banking lifestyle is so tough, what’s the upside?

First and foremost, the money.  There are very few careers that pay as well as investment banking, especially taking into account the level of risk (trading or hedge fund compensation, while potentially equal to or vastly exceeding that of banking is significantly more volatile).  Second, the exit opportunities.  Many people treat investment banking as a stepping stone to other finance careers, including private equity and hedge funds.  Third, for what you learn.  Being a junior investment banker teaches you two things.  It teaches you about finance and it teaches you how to work and survive in a difficult and detail obsessed environment.  Both skills are likely to prove valuable regardless of future career choice.  Fourth, for ego.  Many people get a kick out of telling others that they are in banking and for seeing their deals on the front page of the Wall Street Journal.