I am a US American who teaches English in Taiwan, mostly to adults, and mostly for special purposes (business and academic English, pronunciation, dialogue coaching for performing artists). I have been teaching for 8 years here. Prior to moving to Taiwan, I was the co-founder and vice president of a chain of bakeries. Before that, I was an administrator and instructor at the Fu Foundation School of Engineering and Applied Science, Columbia University.
Prior to that, I was a research assistant at Stanford University School of Medicine.
I have a master's degree in (try to say the whole thing in one breath): Psychology and education: developmental psychology. Teachers College, Columbia University.
I am better at using English than I am at explicitly understanding and explaining grammar. I have come to learn more about it explicitly only since becoming an English teacher. I strongly believe that we learn languages (native and later-acquired) almost entirely unconsciously from hearing and reading the language when we understand it in situations where the messages being communicated are compelling; that is, most of us learn best when we are not trying to learn facts about the language itself. I think that learning grammar directly and explicitly is only useful for people who love it or need to learn it for a clear purpose. I think that most or many people who learned English in large part by studying grammar, essentially learned English incidentally in using English around the topic, and that most or many would have learned more if they had instead used English to read about, learn about, talk about, something more interesting or valuable to them.
See http://sdkrashen.com/ for more about second language acquisition.