'He's very ugly,' said one of my students, referring to a pen wrinkled pensioner I'd drawn on the board.

'Yes, he is,' I agreed.

'Is he Indian?' another one asked. And the mood moved from light humour to blatant racism, before I had a chance to catch a breath.

'Monkey,' said a studious looking girl on the front desk, and laughter hid under tables, words from my training manual running in my mind.

Students making racist or sexist remarks: Avoid getting angry, and tell them that these comments would not be acceptable in Western culture.

I told them; they nodded almost guiltily. The lesson continued, but my developing affection for Korea was shaken.

That night I got talking to a Korean girl at a food stall. She had a gentle smile and soft, cascading hair. I decided to refresh myself with her thoughts on other cultures.

'I don't like Chinese. It's not thought, it's just some sort of feeling.'

Steam got into my eyes, and the wide, humid streets took on a cold, closing rigidity.

Over the following days I ran classes on Stereotypes and Discrimination. Asked what stereotypes were prevalent in Korea, the students reported common conceptions of the Indians, the Chinese, and the Americans. They probably kept their ideas about the British to themselves.

Though they were aware of the stereotypes, many students said they 'didn't think that'. As with any place in the world, some people have bigoted attitudes while others are more tolerant.

We all judge people by appearance. If they're black, we notice. If they're Indian, we notice. If they don't seem local, we ask them where they're from. Their answer, just a few words floating in the moment, is pulled down with a package of preconceptions. And ideas are formed before the conversation takes shape.

We judge people by attractiveness, accent, occupation, sexuality, gender, mannerisms, dress, hair colour, facial shape, choice of beverage, sporting allegiance, political opinions, interests, proclivity of nasal hair and facebook profiles.

Young people form groups based on musical tastes. As if it matters. There's no reason why a jazz enthusiast can't enjoy a drink with a metaller. Bullies make jokes, their togetherness created by their common victim. Football fans kick each others heads in, fuelled by the need to belong.

In Korea, as elsewhere, people gather into groups and slag off other groups. But there are differences in South Korea that can make it appear to be a racist culture (Is it racist to say a race is racist?).

Appearances are more important here than in the west. Korean businessmen are immaculately dressed, while ten per cent of women have had plastic surgery. Ten Years Younger, whisper billboard promises, and models smile as they impose their false ideals.

Korea is not multicultural. 'Even if you stay here 100 years, you will not be a Korean,' a friendly man told me outside a 7-11. 'What are you?' students asked a Korean-American teacher, bewildered by his Asian appearance and American demanour.

'I don't like the French football team,' continued the man outside the 7-11, 'many are not French, original French.'

'You mean they're black?'

He giggled shyly.

'You don't like black people?'

'No I like black people, I like all people, but I think they should play, their own country.'

Dongsoo clearly wasn't racist; he was merely unfamiliar with emigration and multi-culturalism. Korean society, western and developed on the surface, contains ways of thinking vastly different to our own.

But being surrounded by this strangeness, this different way of thinking, fills me with fascination. The challenge of understanding a society I won't understand, it's advantages, it's disadvantages, it's unfolding newness, is one of the things I like most about being abroad.