First Trump tenure, word has it that folks from the Pentagon would visit the White House and be horrified after receiving what seemed to be a series of often conflicting orders / demands from Trump that day to day he would seem to forget he ever said. White House staff and advisors not wanting any ire from Trump were of no help to Pentagon officials to clarify things. In response they established a rule that they wanted a signed order before taking any serious action, otherwise they ignored stream of consciousness type demands, in a few cases these included talk of assassinating foreign leaders.
There is something about the combo of "oh he just says things sometimes" non seriousness along with autocratic tendencies that seems very dangerous.