I went to Harvard Business School to learn how to start and run a business. While I learned an enormous amount about what it takes to be successful in business, twenty years later I now know that no business school – not even Harvard – can teach the core requirements of entrepreneurial success. Schools like Harvard can teach analytic frameworks and provide written case studies about entrepreneurs.

However, these schools can’t give people the inner attitudes and ways of being of a true entrepreneur. Here are eight things they can’t teach you at Harvard Business School:  

One: Passion. Entrepreneurs are passionate about solving a problem for a target market and profiting from their solution. This passion drives us forward when others doubt them. It pushes us to overcome huge obstacles. It keeps us going when ordinary people would give up. 

Two: Ethics. Despite courses on ethics at Harvard and other top business schools, Harvard MBAs are not exactly leading the world in integrity. Successful business people understand that we work in a community and have an obligation to be good corporate citizens – even if it means giving up profits to do the right thing. We also know that people do business with those that they trust and respect, and integrity is a big part of building trust. 

Three: Appropriate confidence. Many people who come out of Harvard Business School are extremely confident (even arrogant), but not necessarily competent. In fact, at least one of my entrepreneurship professors told my class that a recent Harvard grad is likely to drive a business into the ground without a few years of solid seasoning as a manager. The successful business owner has confidence backed by substance. We know our market, we know the problems our market faces, and we can deliver a consistent solution to those problems. We keep our ego in check, and yet we have the confidence to push forward in good times and bad. 

Four: Street Smarts. Entrepreneurs know how to find practical, creative, low-cost ways to get things done. That is something that no school can teach. Professors and text books are rarely street smart! 

Five: Personal Responsibility. It is easy to go to a university and be an outside observer. Students don’t have personal responsibility for meeting payroll, keeping employees and customers safe, and assuring positive cash flow. Students are like Monday morning quarterbacks, able to question the judgment and risks of others. Entrepreneurs know that the “buck stops here.” We have no choice but to take 100% responsibility for anything that happens in our business. For instance, this week I was very impressed to see the CEO of a restaurant chain serving coffee to customers. I asked him why he was doing that and he explained that a couple of his wait staff didn’t show, and he was the only one who was available to step in. That’s personal responsibility! 

Six: Resilience. If you want to learn resilience, start a business. Entrepreneurs know what it is like to expect an investment come through, and then have it fall through at the last minute – while still having to keep the business going. Entrepreneurs know what it is like to get a bad shipment from a vendor – while still having to ship product to impatient customers. Entrepreneurs know what it is like to have a key employee get sick or leave – and then have to step in for them. We can bounce back from almost any setback and keep going, even if it means rebuilding our business from scratch after we run out of cash. 

Seven: Relationships. Business schools are great at teaching you frameworks. But they can’t teach you how to get along with diverse people, resolve conflicts, influence employees to go the extra mile or improve their standards, or build loyal relationships that result in streams of referrals coming your way. 

Eight: Leadership. Finally, leadership is a vague term and business school classes talk endlessly about what makes a good leader. Entrepreneurs know what leadership is. It is a way of being. Successful businesspeople have it, and it can take years to develop and improve. No business school can teach it.