I learned this when I didn’t get a promotion that I was up for at Starbucks . It was really hard, because it was a job that I wanted to do. I was the CFO for North America, and I was up for the head of the North America job. It went to somebody else from outside who the board thought had a little bit more experience than I did. I took that really hard.

Then they said, “We want you to go do this little assignment in Asia.” It ended up being the best career move of my life.

The international group was at a point where it was not doing very well. I was moving into a group that wasn’t succeeding. So that was a risky part, to go in there. I had been feeling like I hadn’t succeeded, then what I actually found was I had been given the best opportunity of my life.

I have a great mentor, outside of the company, whom I’ve known for a lot of years. I go have my pity parties with her. It’s a safe environment to let it all out. She’ll look at me and call me on my game or my story and say, “Right, now what are you going to do about it? Get yourself back in there, pick yourself up, and go be who you know you can be.”

So that’s what I did. In January 2004, I took the helm of Asia Pacific Group, picking up 10 countries. I restructured our China business to a position of growth and made even bigger strides in Japan, a joint venture with 20% public ownership. When I took over, the stock price of Starbucks Japan was in the low teens, after going public around $64 a share, and the venture had been unprofitable for all but one year. Same-store sales growth was negative and new store growth had slowed to 40 stores per year. Working closely with the Japan management team, my team developed a plan to turn the business around.

By the time I left my position in February 2007, same-store sales were up double-digit, new store growth was 100 stores per year, the stock price was back to the low 50’s. The company was profitable, and its value had increased by over $200 million. It was a great way to finish my career at Starbucks.

But I knew that I wanted to be a CEO.  And I knew I couldn’t do it at Starbucks.  Your first opportunity isn’t running a $10 billion company.

I also knew that I’d grieve leaving Starbucks. I took a year off, in between, very deliberately. Being in Asia 240 nights a year, in hotel rooms — that’s a lot for almost four years. I wanted that time with my family.

So I made the decision. I had my successor in place. It was time to go. And I left. I just let myself be myself, and reconnect for a year.  Then the opportunity with lululemon came from that.  It was the day after I decided I would go back to work that I got the call from Bob Meers, the CEO of lululemon, who was looking for his successor. It just happened. I was ready. It was a great opportunity.

Christine Day spent two decades at Starbucks and rose to president of its Asia-Pacific division. She became CEO of Vancouver-based Lululemon Athletica in June. She’s had a giant challenge in a punishing retail environment. The stock is down nearly 80% to $11 this year. Read more from Day, her “Best Advice I Ever Got,” in the current issue of Fortune.