That tweet came shortly after "Morning Joe" co-host Joe Scarborough had called attention to an Axios scoop in which schedules leaked from the White House for the past four days suggested that Trump had spent 50% of his day on "executive time" -- shorthand for the hours that include watching cable TV and tweeting.
Aside from suggesting Trump is not actually as rich as he says he is, there is no easier way to trigger the President's anger than to say he simply doesn't work all that hard. Trump has long maintained that a) no one works harder than he does and b) his commitment to said hard work is the reason for his success.
The idea of Trump as the hardest working guy out there fits the broader story he has been telling himself -- and everyone else -- about his own life. To hear him tell it, Trump was always more comfortable with the blue collar workers out on his various projects rather than in boardrooms with a bunch of executives. (That sentiment runs directly counter to Trump's decision to make a reality TV show that centers around him in suit and tie in a boardroom, but whatever.)
Trump as the everyman -- or at least as the rare rich guy who understood the concerns of the everyman -- was a central theme to his 2016 campaign. And once he won the White House, he and his aides made sure to stress that he was thankful for the support of working people and looking out for them every day.
"The President is one of the hardest workers I've ever seen and puts in long hours and long days nearly every day of the week all year long," White House pres secretary Sarah Sanders said recently. "It has been noted by reporters many times that they wish he would slow down, because they sometimes have trouble keeping up with him."