...it was tough, but I learned so much...

Seems like a common theme: people discuss a terrible time in their professional life -- a new job, a tough class, a summer working on the potato farm -- it doesn't really matter what, exactly. The point is that many, many "important" people who have accomplished a lot in life had to start somewhere. They did something (or some number of things) that were uncomfortable, dirty, difficult, or just plain miserable. But they were smart enough to seize the opportunity to learn and grow and move forward with those lessons learned making them a better person.