I despise Donald Trump. For me, it's not a party line issue. It's not his bizarre quaff or his inability to speak in complete, coherent sentences. It's not his loud mouth antics, his blatant bullying or even the size of his ... fingers. In fact, it's not even his position on a number of core issues.

I despise the Donald because he represents the single most detestable quality any leader can display--he's a "Do as I say, not as I do" kind of guy. He's a spoiled rich kid who believes his vicious temper will get him anything he wants. 

This same quality has been the undoing of "successful leaders" since the beginning of time. The Kahns in Mongolia. The Roman Empire. As much as I resisted watching the GOP debate debacle last week, in the interest of remaining informed, I did. Aside from the fact that it was like watching a gruesome season finale of Housewives, Trump violated every principle that should underpin a great leader.

Great leaders are motivators. They raise people's spirits. They unite people under a shared vision for doing great things. "Make America Great Again" is not a vision. It's simply a way of garnering support from people who are disenchanted with "the system." It doesn't empower people--it makes them align their anger. As a country we were already anti-the-establishment. What we need is a leader who can bring people together, not divide us into further factions. Great leaders encourage people to become better versions of themselves and they don't confuse financial success with leadership.  

Following are five lessons everyone needs to learn if they want to be a leader. Maybe Trump University will incorporate these into its future curriculum after it answers to the court. 

1. When Things Get Hot ... Keep Your Cool

It's fascinating to watch how people respond to being called out on their behavior. If you had been one of Trump's advisors you would work with him to ensure that when the pressure was on, he remained cool. He didn't. He loses his cool and when he does, he makes critical mistakes. He launches personal attacks, contrives non-sensical responses and exposes himself as someone who's unable to remain calm amidst chaos. A leaders composure is always one of their greatest assets.  

2. Arrogance Will Ultimately Become Your Greatest Enemy

We're all a little arrogant, but it's important to realize expressing our arrogance is actually a sign of deep seeded insecurities. Leaders who are massively insecure have historically trampled those who stand in their way. Trump takes arrogance to another level. Recent comments from Pena Nieto, Mexico's president, about the extensive damage Trump's done to U.S.-Mexican relations were met by Trump's retort that "the wall just got 10 feet taller." His inability to be humbled, to take criticism and to admit his faults will ultimately lead to his own undoing.  

3. Keep Your Inside Voice Inside   

Lincoln said it best. "It's better to remain silent and be thought a fool than to open your mouth and remove all doubt." We all have a dark side. An inner voice that says outrageous things. Trump doesn't know how to keep his darkness to himself. Even if you believed we should meet fire with fire when it comes to terrorism and our interrogation tactics, making outlandish statements about undermining the Geneva Conventions need to be carefully considered. Leaders need to realize that the words they choose radically change the receptivity others will have towards their ideas and convictions.   

4. Take a Stance and Be Consistent

There's no doubt, Trump plays to his audience. He's a puppet responding in the moment, and he's been inconsistent in his position countless times. Great leaders need to take a hard stance while remaining open and flexible. When you change your position to appeal to an audience, eventually you'll be exposed for an inability to be honest. And without honesty, leaders lose the respect of the people they lead. 

5. Get People to Work With You, Not For You

Henry Ford once said, "Coming together is a beginning. Keeping together is progress. Working together is success." There are two distinct ways of managing: Believing that you rule the roost, or believing you help lead the pack. Telling people that they will do what you tell them to--and believing they will abandon their own convictions and ethics--is a leadership style reserved for maniacal dictators. This attitude is precisely the reason Trump is being compared to Hitler. 

Great leaders choose their words wisely. They speak honestly. They have courage and conviction. They look for ways of uniting people. They bring together generations. More than anything though, great leaders set aside their personal agendas, and encourage diplomacy over divisiveness.

One of the greatest leaders in modern times (if not all time) was Nelson Mandela. He displayed the quintessential essence of leadership. Upon his release from prison and in his journey towards uniting a country torn apart by hatred, he chose the high ground. He said, "As I walked out the door toward the gate that would lead to my freedom, I knew if I didn't leave my bitterness and hatred behind, I'd still be in prison."

Great leaders are selfless. Their purpose has to trump their self interests as they quell their egos in pursuit of shared progress. If you want to be a great leader, whatever you do, don't be like the Donald.