Don't really like the responses from some of the coaches either. In theory, I would absolutely agree that in order to be successful and 'happy' you should work a job that you absolutely crave and would enjoy every minute of the day performing! In practice, let's get real. The chances of you finding out which career that is, is low (even after a few years experience most people don't have it figured out!)
My advice would be to stick it out for 1.5-2 years at McK until you find out (or have a better idea) where your true passion lies. The hours will be long, although less than corporate law and IBD. But the experience will be worth it (along with the brand name)!
Good luck :)
p.s having MBB on your CV along with the experience you gain can only be seen as positive. I'm talking from experience :)
edit: you should certainly give it your all in the time you are at the firm. People don't want to work with those who are unmotivated, particularly given the stressful environment. So a tip would be to keep your head down, contribute good work towards your teams, and most importantly see this as a learning curve to something greater!
Thanks for the tip. I always knew that I want the consulting toolkit. I really enjoyed casing. And I want to get into Business Strategy roles in the industry. It is the hours I am scared of after talking to a few ex Consultants who left McKinsey. It seems just as bad as banking now as I learn more.