My two cents:
I agree that an undergraduate education is about "finding yourself," but as an engineer, it was more than that. I learned how to think analytically, assess problems, and come up with creative solutions. Granted, many of my classmates were better at this than me, I think many of them were lacking the important aspect of communication skills. You can be the best engineer in the world, but if you can't articulate your results, they are essentially worthless.
So if I'm so perfect <sarcasm>, why an MBA? Easy enough...as I have progressed through my career, I have encountered problems that involve aspects that are too complex or too intricate for me to solve using the tools I currently possess. Do I expect an MBA to give me all of those tools? No, but I expect that continuing my education will help me to fine-tune my problem-solving skills into something that will make me more efficient and successful at addressing business issues. Yes, an MBA is about networking, but it's also about getting exposure to a diverse group of students who can suggest different ways to attack a problem. My hope is that I can ultimately perform better in my desired role than I could without an MBA.