1. Real and exaggerated historical and territorial disputes: Goguryeo, Gando, speed skating sign stunt, historical fantasy dramas showing half of China under Korean rule

2. Exaggerated or fictitious cultural "thefts": Confucius was Chinese, Chinese characters were invented by Koreans, registration of Dano/Duanwu with UNESCO

Koreans are the Polacks of Chinese ethnic/nationality jokes, which mock Korean claims to have invented/discovered/created everything. After hearing and reading Chinese rants, I feel most gripes are without merit, but for whatever reason, Koreans are a favorite target. I think there is also envy at the economic success and political freedoms of a small, former tributary state. Save for South Koreans and Thais, Chinese people enjoy a higher standard of living and greater political and economic freedom than their neighbors.

What could average Chinese be hearing about South Korea, and in what venues, to warrant such a rating?

South Korea does not have any real territorial disputes with China that could play out frequently in the media.

South Korea doesn't have Korean troops stationed throughout China.

I don't think South Korea is a powerful enough to be viewed as a post-modern colonizer.

So what factors are being played up by what social outlets to generate such a wide-spread negative view?