just for the record. '정' does not actually translate to English well. I would say that is is closest to 'Emotional Attachment' more than anything. I would try and explain it in more detail but honestly it would involve writing an essay. Just remember that it doesn't translate exactly.
"The core of 정 is magnanimous unselfish giving. Unselfish in that you are giving without expecting anything in return. That is, you don't run a calculator in your head. The point of 정 is that it’s not rational. In that sense, it’s related to the notion of altruism.
It can also refer to warm and kind gestures shown toward others, especially towards strangers. It's more of a personal trait in this case. When people say Korean people have a lot of 정, it means they are kind to foreigners (and offer them to eat a lot of meal they prepared. )
When you spend a lot of time with someone, we say 정 들었다 (they are bound with 정). This is when two people feel special affiliation with one another simply for the sheer amount of time spent together. Actually what is considered a long time depends. I can feel sad that you are leaving after staying with me for 1 day, especially if you spent time in the same space together.
An elderly owner of a restaurant may have the tendency to give extra portions to customers without extra charge because she is someone whose heart is naturally filled with 정 and treats customers not as customers but treat like her sons and daughters.
When a married couple of 10 years have a lot of fights, and they seem on the surface to be unable to stand each other, an outsider may say, they should get a divorce. But they may be still living together because of 정. In fact, there is an expression called 미운정(미운 is an alleviated version of “hate”). This refers to a special bond that is developed after having multiple arguments with another. One reason 미운정 develops may be because these arguments lead to a deep and intimate understanding of each other.
On a side note, 정 is a word that is thrown away a lot. 정 certainly exists in Korea but how sincere people are when they say they are doing something out of 정 depends on the individual using the word.
The word 정 can also be used to mask a serious domestic violence that calls for legal remedy. (For example, "Why don't you get a divorce when your husband is beating you so much? I have developed a 미운정 toward him.")"