(CNN) Empathy has never been a strong suit for Donald Trump. Even as President, he tends to see everything through a simple lens: Me, me, me and how does this affect, well, me.

Which brings me to Wednesday morning and the 18th anniversary of the terrorist attacks on September 11, 2001.

Trump started his day -- as he so often does -- on Twitter. And even as 8:46 a.m. approached -- the exact time that the first plane hit the World Trade Center -- Trump kept at it.

"In a hypothetical poll, done by one of the worst pollsters of them all, the Amazon Washington Post/ABC, which predicted I would lose to Crooked Hillary by 15 points (how did that work out?), Sleepy Joe, Pocahontas and virtually all others would beat me in the General Election," tweeted Trump at 8:12 a.m . "This is a phony suppression poll, meant to build up their Democrat partners. I haven't even started campaigning yet, and am constantly fighting Fake News like Russia, Russia, Russia. Look at North Carolina last night. Dan Bishop, down big in the Polls, WINS. Easier than 2016!"

But he wasn't done. "If it weren't for the never ending Fake News about me, and with all that I have done (more than any other President in the first 2 1/2 years!), I would be leading the [Partners" of the LameStream Media by 20 points. Sorry, but true," he tweeted at 8:19 a.m

Once Trump got to the Pentagon to lay a wreath at the site of the memorial to those lost when a plane hit the building 18 years ago, he quickly turned the subject to himself.

"I vividly remember when I first heard the news," Trump said. "I was sitting at home watching a major business television show. Early that morning Jack Welch, the legendary head of General Electric was about to be interviewed, when all of a sudden, they cut away." Trump then went on to talk about the various theories circulating in real time about what had happened -- "It was a boiler fire, but I knew that boilers weren't at the top of a building. It was a kitchen explosion at Windows on the World. ... Nobody knew what happened" -- before adding that he "saw a second plane go into the second tower" from his office window in midtown Manhattan.

Later in the speech, Trump sidetracked to talk about his decision to cancel planned talks with the Taliban at Camp David. "We have hit our enemy harder than they have ever been hurt before and that will continue," Trump pledged, while adding that while the US would not use nuclear power in Afghanistan, that "they have never seen anything like what will happen to them."

While there are some elements of where-were-you-when-ism that go around the internet on every anniversary of the 9/11 terror attacks, it's striking the extent to which the President of the United States -- speaking to a group of victims' families -- looked inward. Yes, he talked about what he was doing that day. What he was watching on TV. What he thought had happened. But then, his latest drama on how he decided to cancel the talks with the Taliban.

That, plus his inability to control himself from lashing out on Twitter about polling that suggested he might lose in 2020, speaks to something deeply true about Donald Trump: He is someone, unlike our past presidents of both parties, who rarely puts himself into someone else's shoes. He likes his comfortable (and expensive) loafers very much thank you.

That lack of empathy was, in the eyes of many longtime political observers, Trump's Achilles heel. I can't even tell you the number of conversations I had during the course of the 2016 campaign in which politicos predicted that Americans would never elect someone who couldn't, in the words of Bill Clinton, feel your pain.

Except that voters didn't care. Or more accurately, they cared about other things more. Just 15% of voters in 2016 said that a candidate who "cares about me" was the most important quality in deciding their vote. Hillary Clinton won that group by 23 points. Trump still won.

So voters knew what they were getting. But at solemn moments like today, it's hard not to be struck by just how different Donald Trump acts as president from, literally, every person who has held the office before him.