Nasser took over the Suez canal as he was entitled to do as it was in Egypt.In 1967, when Nasser was dick-swinging around the Middle East, there was a UN force stationed in Sinai that had been there since Suez to protect international waterways.
Nasser ordered them out and the UN Secretary General meekly complied. With them out of the way Nasser closed the Straits of Tiran to international shipping. Israel said that would be a causus belli and they acted on that.
That led to the Six Day War, which left the West Bank & Gaza in Israeli hands. Had the UN force stayed put, it's doubtful the war would've happened and we wouldn't be where we are today.
The UN force in Lebanon was supposed to ensure that Hezbollah met the terms of the 2006 ceasefire and remained north of the Litani river. They conspicuously failed to do that, which is why we're where we are now in Lebanon.
So you could maybe understand why Israel has no faith in the UN.
The Brits, French and Israelis attacked Egypt.
For once the US were on the right side and told them to back off.
And by the way the UN are always unpopular with states who want to use overwhelming force against states with little means of defense.