Two blowhards are busy threatening each other with nuclear weapons. How likely is it that something goes terribly wrong? My guess: pretty likely if Kim Jong Un actually fires a bunch of missiles near Guam. Damn likely if one of those missiles actually hits Guam or lands in Japan.
Kim really can't afford to look weak and Trump may badly need a distraction from the Russia investigation, which may be closing in on either Trump or some of those close to him.
With apologies to Kipling - If you can keep your head when all those about you are losing theirs, you probably just don't appreciate the gravity of the situation.