A marketing professor was picking on stupid products, like Heinz gravy, when a student in the back offered, "I was the product manager for gravy at Heinz. It made us $60 million last quarter. If you'd like to use it for a case study some day, I'd be glad to help you with it."
This particular story is a great synopsis of business school. You are encountering people who may not know what they're talking about, opening yourself up to new data and new thinking, and being polite and constructive about it. Note who is playing each role in this case, too.
And for the cynics in this thread: you only get to complain about MBA's if you can do their job better than they can. I'm not saying you can't, I'm just trying to be fair.