“Dumb as a rock” and “lazy as hell” is how President Donald “I Hire The Best People” Trump just described his former Secretary of State Rex Tillerson.

This after video emerged of Tillerson describing Trump as “undisciplined” and someone who “did not like to read.”

Speaking in Houston Thursday at a dinner to benefit MD Anderson Cancer Center, the former ExxonMobil CEO broke his silence about Trump, telling CBS News political contributor Bob Schieffer that POTUS fired him in March because he got tired of Tillerson telling him some his ideas, while interesting, were illegal.

“We did not have a common value system,” Tillerson told Schieffer Thursday night. “When the president would say, ‘Here’s what I want to do and here’s how I want to do it,’ I’d have to say to him, ‘Mr. President, I understand what you want to do, but you can’t do it that way. It violates the law. It violates a treaty.’…He got really frustrated.”

Tillerson speculated Trump “grew tired of me being the guy every day that told him, ‘You can’t do that, and let’s talk about what we can do,'” Tillerson said.

In Tillerson’s defense, Schieffer asked him to describe POTUS. Tillerson revealed he had never met Trump until the day he was named secretary of state, which does not say much for Trump’s whole “hiring the best people” process.

“He acts on his instincts, in some respects it looks like impulsiveness,” TIllerson observed.

Tillerson admitted it had been “challenging” to transition from “the disciplined, highly process-oriented ExxonMobil Corporation… to go to work for a man who is pretty undisciplined, doesn’t like to read, doesn’t read briefing reports, doesn’t like to get into the details of a lot of things.”

Instead, TIllerson said, Trump would tell him, “‘Look, this is what I believe and you can try to convince me otherwise,’ but most of the time you’re not going to do that,” Tillerson recounted.

Here is the interview that triggered Trump: