The drop in the approval rating of South Korean president Lee Myung-bak from about 50% to 20% in a little over three months is rather impressive. Elected with the largest margin of victory among South Korean presidents, he's becoming unpopular really fast.
I think many Koreans are overreacting in their protests against the import of American beef. There has only been two cases of mad cow disease discovered in the US, which appears to have been contained before spreading further. The probability of contracting the disease from US beef is so low that it's a little hard to understand the level of conflict that's arisen from this issue. This is especially so since there has been less than five discovered human cases in the US itself who have contracted the disease, and it's not even clear that they contracted it from US beef.
The level of protests is bewildering, especially considering that there hardly seems to be any protests against Chinese food imports, where there is an actual and persistent history of contaminated foods being imported. At least the protests have not been particularly violent overall.