By John A. Byrne | Reprinted from PoetsandQuants.com

They may be Masters of the Universe now, leaders of Fortune 100 companies, commanding tens of thousands of employees and pulling down multi-million-dollar pay packages every year. But when these Fortune chief executives were mere MBA students, they felt as overwhelmed, as intimidated, as dumb, and, in some cases, as completely broke as many of today’s MBA candidates.

Most of them earned their degrees before the big boom in MBA education, when business schools pumped out fewer numbers of MBAs, and it was, frankly, easier to get into even a Harvard or a Stanford than it is today. Did the degree make a difference? Several Fortune 100 chieftains say that it was the MBA that opened the door to opportunities that otherwise may have been closed to them. But it was no cake walk.

GE’s Immelt: “Overwhelmed at Times”

“Business school,” recalled GE’s Jeffrey Immelt in a recent CNBC interview, “Is one of the most intense times of your life. There are times you do feel overwhelmed from the standpoint that it’s midnight, I have another case to read, I don’t really understand the subject material, and you say, ‘Gosh, what am I going to do?’

“And then, sometimes you are sitting there in the middle of a discussion and someone says something so smart that you hadn’t thought of and you think, ‘I am a dummy. I’m an idiot. This guy is so much smarter than I am.’ So you do feel inferior at times. You do feel overwhelmed at times.”

J.P. Morgan’s Dimon: Always Prepared for Class

One of Immelt’s classmates in Harvard’s Class of 1982, Jamie Dimon, now CEO of J.P. Morgan Chase, said he never came to class unprepared. Recalled Dimon: “The professor would call on someone and it was completely obvious to everyone that the person hadn’t read the case at all. They were trying to weave a whole story from that first page.” When the CNBC interviewer told Dimon “that must be a little uncomfortable,” the J.P. Morgan chief made clear it was never him who had come to class unprepared.

“I think since my time the focus has been more on teamwork, which makes sense,” he added. “Effective leaders are people who work with others and through others to make others better. I visited an engineering school the other day and was most impressed with the students who had completed a field project, who had built something as a team. It was more of a leadership exercise. Any way you can foster that kind of teamwork is important, particularly in business.”

Boeing’s McNerney: “Not a Kumbaya Exercise”

Another Harvard MBA (who was a George W. Bush classmate), Jim McNerney, CEO of Boeing, remembers the sense of competition in class. “There was a competitive spirit in the classroom that simulates the way business is,” he recently told an interviewer from Harvard’s alumni magazine. “The WAC [Written Analysis of Cases] was not a kumbaya exercise, it was about getting it done by Friday at midnight. You do come away feeling prepared for a business environment, which is often more about optimization than coming up with the right answer.”

Many CEOs Call the MBA a Door Opener

For Paul Otellini, CEO of Intel, his 1974 MBA degree from Berkeley’s Haas School was critical.  “I graduated in a recession and my MBA was my initial foot in the door,” he said in an interview with Berkeley’s alumni magazine. “You learn a very thorough, analytical methodology at Haas. We did not have many cases in those days. Instead, we relied heavily on a highly quantitative, data-driven approach to problem solving. That has worked extremely well for me in the high-tech industry.”...