I enjoyed my time at business school. For two years, I was fully immersed in the intense daily schedule of classes and team study sessions.
I studied subjects I had never been exposed to either as a college undergraduate, nor in my first post-graduation job as an account executive at an advertising agency.
I learned how to value multi-billion-dollar companies; how to analyze and optimize manufacturing processes; how to identify patterns and relationships from large amounts of data through statistical analysis; and how to assess the feasibility of new geographic markets for products ranging from toothpaste to credit cards.
But it was only after I had graduated and was back in the working world for a number of years that I discovered just how much I hadn't learned at business school.
Here are six subjects that I didn't learn at business school (but wish I had):

1. How to lead others in the absence of formal reporting lines.

This has to be one of the most challenging things I've encountered in my career over the years, and one that I know many other colleagues have faced as well. How do you persuade others, and even lead others, when they don't report to you, or aren't otherwise formally incentivized to support you or collaborate with you?

2. How to tell stories that move people to think, change, and act.

The best business leaders I've observed over the years know how to inspire people with stories about how they've encountered challenges and overcome them, and the lessons they've drawn from their experiences. How effective leaders tell their stories -- through rousing, "rally the troops" speeches, or inspiring office memos-- are powerful skills that I don't remember learning when I was at business school.

3. How to build and maintain a positive reputation.

When I was at business school, an alumnus returned to campus one day to give a talk about what it was really like to be back in the working world after graduation. He was working for a top-tier investment banking firm at the time, and I'll never forget what he told us: "You can spend an enormous amount of time building up your reputation, but then it can all come crashing down in an instant. Guard your reputation well."
Knowing how to build and maintain your professional reputation, or the reputation of a company or other major institution, is both art and science. Yet, while we spent hours learning how to calculate the value of multi-billion-dollar companies, I don't recall spending time learning how to measure the value of a company's reputation.
We didn't study how successful companies built and preserved one of their most important intangible assets -- their reputation. Nor did our case studies cover the lessons learned from companies that have seen their hard-won reputations tarnished overnight. 

4. Understanding how digital technologies work "under the hood."

When I was at business school 20 years ago, Netscape Navigator (what's that?) was the browser du jour, and the internet was in its infancy. Today, the internet is bigger, faster, and the technologies far more complex than when I was clicking my first hyperlinks. And the value that has been unleashed through the power of internet technologies is enormous.
But are business school students today learning what really happens "under the hood"? Do they have a familiarity with the software and hardware technologies that power the businesses they are entrusted with leading?
Even if today's MBA students never decide to launch a tech startup or go to work for a technology company, learning how internet technologies work "under the hood" can be of immense value to them when they need to hire, train, and retain the engineers and digital marketing experts who are at the frontlines of today's digital revolution.

5. How to become a lifelong learner.

By the time I left business school and joined my firm, I had earned an undergraduate degree and two graduate degrees, including my MBA. I thought my education was done.
How wrong I was!
I discovered early on in my career that I needed to continuously learn new things and develop new skills if I wanted to keep up with the rapid advances in technology, and adjust successfully to the changing priorities in my firm and the impact of those changes on my role at work.
Cultivating a mindset of continuous learning, and knowing how to identify relevant learning resources, from online courses to books, videos, and podcasts, are skills that can be immensely beneficial at all stages of one's career.

6. How to find meaning and purpose outside of work.

This took me a little too long to learn: no matter how much enjoyment or fulfillment you derive from work, it's unlikely to satisfy your yearning for meaning in life. You'll probably need to find it elsewhere: Through raising a family; making close friends; through the pursuit of "passion projects"; or, perhaps, through spiritual inquiry or religious observance.
Even if an MBA program doesn't offer a course, acknowledging the importance of the topic, and encouraging discussion around it, can be a valuable addition to a curriculum whose main objective still seems to be teaching future business leaders how to maximize shareholder value.
Given the lofty price of today's MBA programs -- tens of thousands of dollars for tuition, and the opportunity cost of putting your career on pause for one or two years and not earning income during that time -- business school students should learn a broader array of subjects that can prepare them to successfully lead organizations in an increasingly complex and constantly changing world.