One of the hallmarks of great business leaders (and presidents) has always been their ability to laugh at themselves (especially in times of crisis).

When it comes to politics in particular, self-deprecating humor has enabled many a commander-in-chief to project authenticity, humanity and likability (while helping to diffuse the crisis du jour).

My personal favorites include Lincoln, FDR, JFK, Reagan and, believe it or not, W.

Each had the ability to find the humor in a head-on assault from the competition and, in one, way, shape or form, pivot by poking fun at himself.

Reagan’s rebuke to skeptics who suggested he’d lost touch with reality during the 1984 debates may be my all-time favorite example:

Many political pundits believe that single, self-deprecating statement re-elected Reagan.

I raise the subject of self-deprecating humor for two reasons:

1.) Trump’s total lack of self-deprecating humor is one of his most serious character flaws. Instead of deflecting, and redirecting the slings and arrows of outrageous fortune by laughing at his own flaws, The Donald goes postal (Note: I’m not suggesting he could, or should, make light of the sexual assault accusations, but there have been countless, previous missed opportunities he could have used humor as a weapon).

Most recent case in point: The Donald’s Sunday morning Tweet lambasting the laugh-out-loud funny Saturday Night parody of the most recent presidential debate. I thought it was balanced and poked fun at both candidates in hilarious ways. But, Trump disagreed, and missed a huge opportunity to share in the absurdity of it all. Instead, he lashed out at SNL and Alec Baldwin alike. Very bad move.

2.) I’ve based my entire career on self-deprecating humor and have used my “Expect Less” motto in both personal and professional settings. It enables me to inject humor in a presentation or performance by saying, “Hey, I warned you.”

While I’d never suggest I’m a great, or even decent leader, my self-deprecating humor has served me well over the years and, in fact, permeates our firm’s culture and has helped us win countless workplace awards (insert latest Fortune citation).’

Students of political history, communications or business in general should study a leader’s response to a crisis. His or her ability to show humanity, authenticity and, yes, self-deprecating humor separates the good from the great. Or, if you prefer, the least likable from the less-than-least likable.