I am a Canadian (although most assumed I was American) who lived in Korea as an ESL Teacher and found most Koreans to be very welcoming. Both students and coworkers were very interested in sharing their culture with me, as well as learning about North American culture, and showing me around the city.
On numerous occasions random people in the street would help me out. If I looked lost, someone would give me directions, if I needed to put air in my ball, a shopkeeper would offer a pump, once, an elderly woman at a bus stop gave me a bag of freshly picked chestnuts for no apparent reason, cab drivers often wanted to practice their English with me, and the list goes on. There were a few negative, ultra nationalistic types as well who obviously didn't like foreigners in general, but I'm sure you'll find those in any country.
With regards to there being a book that shows the country's laws, taxes, customs and ideologies, I found the Lonely Planet guide to Korea to be very useful. The Teaching English in Korea: At a Glance page on our website also provides a wealth of information about living and teaching in Korea:
http://oxfordseminars.com/esl-country-information/countryataglance.php?c=Korea&topnav=1Enjoy your teaching experience, wherever it may take you!