The best thing about TEFL is the chance to work in lots of different places around the world. It’s one realistic way to live in Thailand, which of course is the sort of place where you come backpacking and decide you want to stay. More than two dozen countries have large ESL sectors, for example here is a list of all the countries where the TEFL International Organization has operations:
Argentina, Australia, Brazil, China, Costa Rica, Czech Republic, Egypt, United Kingdom, France, Greece, India, Indonesia, Ireland, Italy, Japan, Mexico, Nepal, Philippines, Spain, Thailand, United States and Vietnam.