One of them is TV ratings. The former reality star has often mused at how much money he's made for TV companies. When a TV show is failing, however, he's also keen to offer his views.
For example, when "The Celebrity Apprentice" -- a show he used to host -- relaunched, Trump wasn't slow to scoff that the ratings were nothing compared to his own. The new show is hosted by Arnold Schwarzenegger.
Of course, Trump has been tied up with a few launch issues of his own. There was the question of audience metrics for his inauguration. There was the Friday night debut of what promises to be a long-running saga on who can come into the US from foreign lands. And just the other day, there was the reality TV show gloss on the introduction of his man for the Supreme Court.
On Thursday, the president asked for divine intervention for the former governor of California. At a national prayer breakfast, he mocked the show's ratings and said, according to CBS News: "I want to just pray for Arnold ... for those ratings."
Schwarzenegger didn't take this on his knees.
Almost immediately, he took to Instagram and Twitter and offered this rebuttal: "Hey, Donald. I've got a great idea. Why don't we switch jobs? You take over TV, as you're such an expert in ratings. I take over your job and people can finally get to sleep comfortably again."
The White House didn't immediately respond to a request for comment.
Corporate types might be amused, however, that Schwarzenegger is happy to openly criticize his boss. No, not because Trump is the president. He's also an executive producer of "The Celebrity Apprentice."
ARNOLD SCHWARZENEGGER OFFERS TO SWITCH JOBS AFTER PRESIDENT TRUMP'S 'APPRENTICE' DIG
President Donald Trump kicked off his comments at the National Prayer Breakfast with a dig at the man who replaced him in his previous TV gig.
Trump said that since Arnold Schwarzenegger took over hosting "The Celebrity Apprentice," the show's ratings have been down. He asked the audience to "pray for Arnold."
"They hired a big movie star, Arnold Schwarzenegger, to take my place, and we know how that turned out," Trump said. "The ratings went right down the tubes. It's been a total disaster. And Mark (Burnett) will never, ever bet against Trump again, and I want to just pray for Arnold, if we can, for those ratings."
Schwarzenegger fired back in a Facebook video, offering to switch jobs with Trump so that "people can finally sleep comfortably again."
"Hey, Donald, I have a great idea," the former California governor said. "Why don't we switch jobs? You take over TV, because you're such an expert in ratings. And I take over your job. And then people can finally sleep comfortably again."
A spokesman for Schwarzenegger also fired back at Trump.
"Arnold is praying that President Trump can start improving his own approval ratings, which were the worst in history for an incoming president, by taking his job seriously and working inclusively," Daniel Ketchell, the spokesman, told ABC News.
The National Prayer Breakfast, which brings together politicians with members of the business and religious community, began in 1953 and is organized by The Fellowship Foundation and hosted by a committee of members of Congress.
Schwarzenegger offers to trade jobs with Trump after President's comments about Celebrity Apprentice ratings
Arnold Schwarzenegger has challenged US President Donald Trump to trade jobs so "people can sleep comfortably again" after being blamed for poor ratings on the Celebrity Apprentice.
Mr Trump used an address to the National Prayer Breakfast in Washington — normally a solemn occasion — to ask the audience to "pray for" new Apprentice host Schwarzenegger to improve the show's ratings.
"When I ran for president, I had to leave the show," Mr Trump told the audience of more than 2,000 people.
"They hired a big, big movie star, Arnold Schwarzenegger, to take my place. And we know how that turned out. The ratings went right down the tubes.
"It's been a total disaster, and Mark will never, ever bet against Trump again," the President said, referring to Mark Burnett, the show's producer and participant in the annual breakfast.
"I want to just pray for Arnold if we can."
Former California governor Schwarzenegger responded quickly in a brief video on his Twitter account, in which he suggested Mr Trump switch jobs with him.
"You take over TV, because you're such an expert in ratings, and I take over your job, and then people can finally sleep comfortably again. Hmm?"
Schwarzenegger premiered as the new Celebrity Apprentice boss premiered in the US in early January, but this isn't the first time Mr Trump has blasted the bodybuilder for poor ratings.
After premiere ratings came in, showing the Schwarzenegger-hosted Apprentice pulled a disappointing 5 million viewers, the US President took to Twitter to brag about being a "ratings machine".