President Donald Trump Andrew Harrer | Bloomberg | Getty Images

Trump called Sessions 'mentally retarded'

Sessions has often found himself in Trump's crosshairs for his recusal from any involvement in the probe of Russian interference in the 2016 presidential election. But Trump also criticized Sessions for his Southern accent, reportedly mocking it and saying of his own administration's attorney general: "This guy is mentally retarded. He's this dumb Southerner … He couldn't even be a one-person country lawyer down in Alabama." Trump also called Sessions a "traitor" for recusing himself from the Russia probe, which is led by special counsel Robert Mueller, and putting Deputy Attorney General Rod Rosenstein in charge of oversight.

John Kelly called Trump an 'idiot'

NBC News had reported in April that Kelly called the president an "idiot" behind his back. Kelly denied the report at the time, calling it "total B.S." But Woodward's book repeats the claim, according to the Post. Kelly repeated that denial in a statement on Tuesday. In a small meeting, Kelly reportedly said of Trump: "He's an idiot. It's pointless to try to convince him of anything. He's gone off the rails. We're in Crazytown. I don't even know why any of us are here. This is the worst job I've ever had."

Trump on Gary Cohn's resignation letter: 'This is treason'

After Trump said in August 2017 there were "very fine people on both sides" of a white supremacist rally and counter-protest in Charlottesville, Virginia, his former top economic advisor Gary Cohn, who is Jewish, reportedly handed him a resignation letter. "This is treason," Trump said, according to the report about Woodward's book. Cohn stayed on until March, resigning shortly after Trump said the U.S. would impose tariffs on imports of steel and aluminum from a variety of countries. Kelly then reportedly confided to Cohn: "I would have taken that resignation letter and shoved it up his ass six different times."

Mattis told Trump the US was trying 'to prevent World War III'

Trump reportedly questioned why the U.S. was spending money and military resources in the Korean Peninsula during a National Security Council meeting in January. Defense Secretary James Mattis responded: "We're doing this in order to prevent World War III." Woodward reportedly said Mattis was "particularly exasperated and alarmed" after the meeting, "telling close associates that the president acted like — and had the understanding of — 'a fifth- or sixth-grader.'"

Trump's attorney warned him not to testify in Mueller probe