Among all of the events of Arab and Muslim history, the establishment of the state of Israel in 1948 appears to be unique.
Muslims have suffered defeats in war beforehand. Christians in Spain defeated the Muslims in the 15th century, Napoleon conquered Egypt, European nations occupied most of North Africa, and the Ottoman Empire kept losing territory and influence from the 17th century until its total disappearance after World War I.
Yet only one event, involving a tiny amount of territory that was all but abandoned by the Arab world for centuries, gets the moniker "naqba", catastrophe.
In what sense is it so important? By any objective measure (number of Muslims killed, number of Muslim refugees, amount of territory involved, the margin of victory), Israel's War of Independence is barely a skirmish in the vast history of Muslim conquests and defeats. (Kuwait expelled more Palestinians in 1991 than Israel did in any war, for example.)
So, what is unique about the establishment of the State of Israel that makes Arab and Muslim blood boil so disproportionately to the actual damage done?
Only one answer makes sense. It is not that the Muslims were defeated, it is who defeated them.
Animosity between Jews and Arabs is as old as the Bible, where the descendents of Ishmael and Isaac always had problems with each other. But as is well known, for many centuries Jews did prosper under Muslim rule more than under Christian rule.
It is important to understand that as a tiny minority in Muslim and Arab countries, Jews posed no threat (and were indeed more similar to the Muslims than the Christians were.) They were clearly second-class citizens, dhimmis. There were still blood libels and other nastiness, but comparatively Jews were well off - as long as they kept their place as dhimmis.
Israel and Zionism changed everything. All of a sudden, the uppity Jews were saying that they had a right to own and control land in the Middle East - equal to the Muslims. The Arab nations could not fit that into their worldview of Jews as naturally second-class citizens, and therefore they attacked the Jews, both in Israel and in their own countries.
What's worse, the Jews had the audacity to be able to fight and win! Muslim pride could not handle such an affront. The weak Jews didn't know their place and this was what caused the Arabs to expel hundreds of thousands of Jews from their midst in the '40s and '50s - an extreme example of pure bigotry that gets next to no mention in the press nowadays.
In some ways, the 1967 war was even worse for Arab pride. They could almost, almost come up with excuses why the hated Zionists beat their combined armies in 1948, but in 1967 they all but guaranteed their people a swift and complete destruction of the Jewish state - and they were routed, by only Jews, with no help from any other country.
More attacks on Arab pride followed: Israel, in a few decades, built a modern and wildly successful society. In the very middle of the failing Arab League nations. They built farms in deserts, they created universities, they built a high-tech powerhouse, they successfully integrated Jews from all over the world. And they did this without any real natural resources. In a short time, Israel's very success at building a nation hurt Arab pride as much as its military successes.
There are two parts of the (specifically) Arab psyche that are at play here. One, as mentioned, is pride. Extreme pride precludes the possibility of admitting mistakes, or adjusting strategy. Even Sadat said that he could not have considered peace with Israel unless Egypt managed to wage a more successful war that 1967 - the Yom Kippur war was a war for pride. (Losing in war is an even bigger deal to Arabs because so much of Arab history revolves around the sword, romanticizing the best warriors.)
The second, related part that needs to be understood is that Muslims in general, and Arabs in particular, seem to have a big inferiority complex. This comes, I believe, from the rise of the West since the Middle Ages. The Arab world went from being leaders in science and art to also-rans, and the Western superiority in all secular areas kept increasing. Now, as long as Westerners stayed West, it is possible to ignore this widening gap. Excuses could be made. But when Israel came about, where a land that had been a wasteland became a modern high-tech mecca (so to speak) in such a short time, it was no longer possible to ignore the obvious lifestyle differences between the West and the Arab world. Everything that the Arab leaders told their people to keep them in place was being shown to be wrong on a daily basis - women could be successful, democracy works, the free market creates prosperity, individualism allows flexibility, Jews are smart and strong, and freedom is a better social model than despotism. Arabs who live in Israel enjoy a higher standard of living and more freedom than any Arab population in the Middle East.
This is why the creation of Israel is a "catastrophe." The threat to the Arab world is not territorial, it is existential - because freedom is not compatible with what Arab leaders want for their subjects. As long as Israel is demonized, they have a chance of convincing the people that Israel is an aberration of history, a speed-bump on the road to eventual Muslim triumph. But the freedom that Israel represents and the quality of life that Israel enjoys is a poke in the eye of Arab pride.
And the fact that it is Jews who managed to perform these miracles makes it all the more painful.