He's incredibly thin skinned for a man who claims to be the "big, bold, brash tell it like it really is" type. Just look at the ludicrous debates over the size of his hands that any normal person would have laughed off. He bears grudges, long, long after normal people would have let things go. Look at his vendetta over the original "little hands/short fingered vulgarian" jibe which stems back to an article in Spy magazine over 30 years ago by Vanity Fair's editor who still gets regular photos from The Donald trying to show how big his hands are. He's viciously vindictive and will throw anything he can at people he feels have slighted him.
To most of us he is coming across as someone who is unhinged and really should be restrained for the good of his own mental health, someone who should not really be trusted with a Twitter account that the likes of Xi or Putin might take seriously, let alone supreme power. I personally hope Xi, Putin et al are sitting back pissing themselves laughing at The Don's rantings much as we have all enjoyed doing when the last Kim or the present one decide to show the world's media what they are made of. But heaven help us all if one of them decides to reply and upsets the mad orange one, he genuinely looks like he's not playing with a full deck of cards and I fear what his response might be.