All President Zelensky had to do was say "thanks for your support" and have the hard conversations behind closed doors. Instead he tried to use high-pressure negotiating tactics in front of the cameras, on Donald Trump of all people. This was clearly a mistake, and now his diplomatic incompetence and lack of basic gratitude and respect will cost Zelensky and his country dearly.
If you can’t tolerate emotional and tactical appeals from a foreign leader for support in a public meeting without falling apart and castigating them, you’re probably not fit to lead our country. This sort of behavior doesn’t befit a parent or even a middle manager, let alone the leader of the free world.