In your career, you’ll work on the one project that will change you forever. It will be something huge, your role will be key and terrifying, you’ll fight with each other, you’ll give up your entire personal life…all to make sure something happens the way it’s supposed to.

I got to be a part of something like that: what I call “living a real life Harvard Business School Case.”  We had a reunion the other day and here are my lessons learned:

1. You never lose the connections you have created with these people.  They will always mean something important to you.

2. You appreciate the bravery. Sure, it’s easy now that it’s finished for others to dismiss the effort. But you know how terrifying every day was as you were trying to complete the impossible.

3. You realize that people are NOT replaceable. Sure, you can put someone else in a role. But the reason why it all worked was because of who was in the role at that time.  Movies succeed or fail due to casting. It’s the same at work.

Most importantly, great things happen because there is leadership throughout the organization. It’s not just top down, it’s every person who’s involved exhibiting leadership in their own way.