(CNN) President Donald Trump started off his Monday morning just like he starts off a lot of his days -- by taunting a Democrat.

"Little Adam Schiff, who is desperate to run for higher office, is one of the biggest liars and leakers in Washington, right up there with Comey, Warner, Brennan and Clapper!" tweeted Trump , referring to the top Democrat on the House Intelligence Committee. "Adam leaves closed committee hearings to illegally leak confidential information. Must be stopped!"

Yes, this is, by now, standard issue stuff from Trump.

In fact, the nickname he gave Schiff on Monday morning -- "Little Adam Schiff" -- is one he's used before. Several times, actually

There was "Liddle Bob Corker" in reference to the retiring Tennessee Republican senator. "Little Marco" was directed at Florida Sen. Marco Rubio during the 2016 GOP presidential primary fight. And, who can forget "Little Rocket Man" in reference to North Korean dictator Kim Jong Un?

Schiff appearaing on Capitol Hill in 2017.

The repeated use of "little" (and its variant "liddle") by Trump is actually a telling glimpse into how he views the world and what he cares about.

To Trump, who is totally obsessed with physical appearance and size, there is no greater putdown than "little." Trump is big (6'3" according to his recently-completed physical) and believes there is inherent stature conveyed by that, um, stature.

So, shorter people -- Corker is 5'7", Un is 5'7", Rubio is 5'9" (I can't find a height for Schiff, but honestly it doesn't really matter) -- are just not as good in Trump's mind. They can never be truly big, like him. And when he wants to put them down, he always goes to height.

And, tall people are, generally speaking, better in Trump's eyes -- solely by dint of being bigger.

When he was in Alabama at a rally for appointed Republican Sen. Luther Strange last year, Trump repeatedly referenced the incumbent's height. "That is the tallest human being I've ever seen," Trump said at one point . "I am tall, I've never seen that. Should be on the New York Knicks." (Strange, despite being 6'9" lost to Roy Moore.)

In making his Cabinet picks, Trump took height (and overall appearance) into consideration as well. This line, from an amazing Washington Post piece from December 2016 about Trump's Cabine t, makes that point:

"Trump's closest aides have come to accept that he is likely to rule out candidates if they are not attractive or not do not match his image of the type of person who should hold a certain job."

Trump's focus on height -- and size more generally -- is why he has long been easily trolled on the alleged smallness of his hands.

While it all began in the 1980s when then Spy Magazine's Graydon Carter and Kurt Andersen referred to Trump as a "short-fingered vulgarian," Trump's concern with his hand size extended all the way into the 2016 campaign.

"He's always calling me Little Marco," Rubio said at a campaign rally. "And I'll admit he's taller than me. He's like 6'2, which is why I don't understand why his hands are the size of someone who is 5'2". And you know what they say about men with small hands? You can't trust them."

Trump, despite being the clear front-runner for the GOP nod by that point, couldn't resist answering Rubio's barb at a debate days later.

"Look at those hands, are they small hands?" Trump said, showing his hands to the crowd . "And, he referred to my hands -- 'if they're small, something else must be small.' I guarantee you there's no problem. I guarantee."

Yes, that really happened. On Planet Earth. In 2016.

There's lots and lots more examples that prove Trump's obsession with size and bigness. (Always remember: A noble spirit embiggens even the smallest man .) His touting of his inaugural crowd as the largest in history. (It wasn't). His tweet about his State of the Union speech being the most watched ever. (It wasn't.) His tax cuts would be the biggest in history. ( They aren't. This quote about Kim Jong Un : "Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!" And on and on it goes.

Big, for Trump, is a good thing. Maybe the best thing. Little is the worst. And judging by his penchant for giving people pejorative nicknames with "little" in them, Trump thinks a lot of people are the worst.