Why are Koreans so much braver than Israelis when faced with the threat of nuclear weapons?

North Korea's second underground nuclear test, much bigger than its first in October 2006, did not cause panic in South Korea. Even when North Korea conducted a short-range missile test only hours after the explosion, to underline that all of South Korea lies open to nuclear attack, South Koreans went about their business as usual. Nobody fled the country to escape from the threat.

How different from Israel, where a recent opinion poll conducted by the Centre for Iranian Studies at Tel Aviv University revealed that almost a quarter of Israel's seven million citizens would consider leaving the country if Iran gets nuclear weapons.

Israeli leaders talk about an "existential threat" to the country's survival, and warn almost daily that Iran is on the brink of developing the bomb.

There are major differences between the North Korea-South Korea relationship and the Israel-Iran one, but they just deepen the puzzle. The two Koreas have actually fought a war in which millions died, and the two countries' troops still face each other across a massively fortified ceasefire line.

Almost every year there are violent incidents along the border or on the seas around the Korean peninsula.

Israel and Iran, by contrast, have never fought a war, and do not even have a common border. Iran has no nuclear weapons, and denies that it has any intention of making any. Nor has Iran ever threatened war with Israel.

Iran's current President, Mahmoud Ahmadinejad, has said the Israeli state should be "wiped from the pages of history", which makes him about the 20th leader of a Muslim country to voice that empty sentiment. However, he has never said Iran should do that job, nor is he in any position to attack Israel. It is the Supreme Leader, Ali Khamenei, who controls Iran's foreign policy and armed forces.

During his 20 years in office, Ali Khamenei has never been involved in a foreign war, nor has he ever echoed the remarks of the excitable Ahmadinejad.

Whereas North Korea finds some pretext to declare that war with the South is imminent almost every year.

So why are Israelis almost hysterical about the Iranian threat, while South Koreans are phlegmatic about the North Korean threat?

It gets even weirder.