From what I have read, Comey's calling Trump a liar was based on the comments that the President made about his present view of the FBI. Comey said, " the Administration chose to defame me and, moree importantly, the FBI by saying that the organization was in disarray, that it was poorly led, that the workforce had lost confidence in its leader". "Those were lies, plain and simple, and I'm so sorry that the FBI workforce had to hear them, and I'm so sorry that the American people were told them". I think there is reason to believe that if the American people were asked for their summation of the current status of the FBI that most would agree with the comments made by President Trump and his Administration. Comey has been engaged in so "many" questionable situations during his tenure with the FBI that he is unable to accept his "failings" and has gone to unlawful extremes to try to save "face". The methods he has used to impart his "imprint" and "idealogical" thought process into his decision making has finally led to his "downfall".