Actually, it is very possible that in the history of the UN, a member was actually laughed at. A member, let alone a sitting member of the Security Council. I will admit that I have not done homework research on this, so I maybe wrong, but right now, it looks like the US may very well be the first UN member to be openly mocked at. Thanks to the Trumpster.
Nevertheless, it is ultimately irrelevant. The most Donald Trump will have is 8 yrs of being president. And everyone at the UN know it is ultimately irrelevant.
It is ultimately irrelevant in the sense and question that if the Trumpster behave 'presidential' would other countries put US interests first? No, each country put its interests first, US interests be damned. Trump maybe clumsy in speech, and often his mouth runs ahead of his head, but have no doubt he is wily like a fox in mind. His ego have been -- not maybe -- bruised. But he is smart enough to know that once he stepped out of the UN building, he answers to the American people and their approval is more important to him than any approval from foreigners. In that, Trump is reflective of American attitude regarding the rest of the world.