The annual Al Smith dinner in New York is that fleeting moment in time when the two candidates for president trade their political divisions for good-natured laughter — at oneself, opponents and others deemed worthy of a ribbing. Rudy Giuliani appears to have forgotten that. The reaction of the former Big Apple mayor known for his love of a good fight can only be described as that of a humorless, “nasty” man.

Democratic presidential nominee Hillary Clinton roasted Giuliani, a former federal prosecutor, for defending Trump’s questionable personal tax practices.

Watch Democratic presidential nominee Hillary Clinton make jokes at the annual Alfred E. Smith Memorial Foundation dinner in New York, Oct. 20.

As she rhetorically strolled through the dignitaries, Clinton said, “And we have Rudy Giuliani.” Just mentioning his name set off laughter. But all the camera found was the unsmiling face New Yorkers were happy was term-limited. “Now, many don’t know this,” Clinton continued, “but Rudy actually got his start as a prosecutor going after wealthy New Yorkers who avoided paying taxes. But, as the saying goes, ‘If you can’t beat them, go on Fox News and call them a genius.’ ”

The crowd roared. Giuliani sat as if he were perched on Mount Rushmore. The look on his face was a flashback moment for me. Back to those days during his mayoralty when jokes at his expense were not tolerated. Remember, this is the same guy who waged a public battle with New York magazine in 1997 ​against its ads on city buses that read, “Possibly the only good thing in New York Rudy hasn’t taken credit for.” A federal judge ordered the transportation authority to restore the ads. Of course, Giuliani disagreed and whined to the press, “I think that mayors retain certain privacy rights, particularly the right to not have your name used for a commercial purpose.”

During his eight years in City Hall, Giuliani alternated between mean and nasty as he and his administration beat crime (and dissent) into submission. His critiques of opponents and adversaries were withering and personal, much like those of his preferred presidential candidate. Giuliani’s reaction Thursday night to a good-natured, yet pointed knock against him was typical for bullies. They can dish it, but they can’t take it — especially from “such a nasty woman.”