The first impression I got of the UN was in the early sixties, when I was a teenager.
My impression?
"An angry rabble of people who don't like America much, shaking one fist in our faces, while the other hand rummages around in our pockets for spare change..."
And my opinion of them has only fallen more, with the passing years. It's a fraud, a swindle, and a scam, wrapped up in sanctimony while it robs us blind.
Your first impressions were correct; the UN has actually gotten worse, since the early '60s.