From The Washington Post, whose investigative team spoke to more than 30 officials at the White House, the Justice Department, the FBI and on Capitol Hill in preparing its story:

Trump was angry that Comey would not support his baseless claim that President Barack Obama had his campaign offices wiretapped. Trump was frustrated when Comey revealed in Senate testimony the breadth of the counterintelligence investigation into Russia's effort to sway the 2016 U.S. presidential election. And he fumed that Comey was giving too much attention to the Russia probe and not enough to investigating leaks to journalists.

There will be more of this. We have a president who is the human equivalent of the worst of Fox News. He has a narrative in his head that ignores all other narratives and all other evidence and all other facts. You can get away with that if you're tucked into a corner of the cable-news world but not if you're president of the United States. 

The great irony, of course, is that Comey created Pres. Trump—we wouldn't have Pres. Trump without Comey's idiotic moves last October—and in the end it ended him. He's Dr. Frankenstein and Trump is the monster. The sad GOP talking point on the Comey firing is that Democrats wanted this; they wanted Comey fired. Sure. But not in the middle of an investigation into Russian meddling in our election. Not by the monster.