Why not teach English in Asia?
Times are tough in North America.  Economic growth rates are down, jobless rates are up, and inflation continues to eat into workers' earnings.  Additionally, worker engagement is at an all time low, and people are unsatisfied with their work.  One of the easiest options for educated English speakers to escape this cycle is to teach English as a foreign language (EFL) in Asia.  
The EFL industry has been evolving quickly over the last thirty years, to the point where a potential teacher has a great number of options.  You can go to China, South Korea, Vietnam, Taiwan, Japan, and other markets.  You can work with kids, teens, adults, or business people.  However, with all this variation, there are some commonalities across the field.  
By the way, I spent 10 years in Asia in three different careers (teaching, market research, entrepreneurship).   I spent the most time - 5 years - teaching.  However, I could have learned the same lessons in much less time, if I had some guidance.  
Here are four reasons why you shouldn't teach EFL in Asia.

1) People have, at best, mixed feelings about learning English and globalization.
Imagine that you wake up one day and everything was different.  People's clothes were different, people spoke differently, and they were using strange new technology.  For most of the world, that is reality.  Globalization has changed the world and no one person was given a choice in the matter.  While most of your adult students are there to take advantage of the new paradigm, they are wary of the changes going on in their world.  They haven't really chosen English, they are reacting to it.

2) You do a lot of free therapy.
Many Asian students are stressed out.  They have too many responsibilities and not a lot of outlets for their emotions.  Very often, I ended up counseling teenage and adult students.  Additionally, a lot of students will have ideas about the west that they've picked up from popular culture.  They want to test these ideas out.  On you.  

3) Student motivation isn't very good.

Unfortunately, most of your students will not be in your class for the joy of learning or the desire to speak with foreigners.  They are there to advance their careers and this shows in their attitude to learning.  Because they lack purpose, many students are unmotivated to take risks in the classroom.  Most show little progress.  

4) Business, management and education practices are lousy.

Transparency International ranks Asian countries quite lowly on their corruption perception index.  (Some of this is unfair because Asian business practices are quite different and outsiders can't tell what is-and-is-not unethical behavior.)  In terms of the office environment, the emphasis in Asia is on face time, not productivity or efficiency.  This can be frustrating to Westerners.  Finally, education practices in most of Asia are terrible.  Asian schools rank poorly, despite massive inputs of money, time and energy.  Asian educational culture is a tremendous drag on society, and everyone knows it (but they don't want to admit to it).

5) People don't like you very much.

Lastly, people don't like EFL teachers very much.  Local people have heard stories of the kind of trashy foreigners that show up to teach.  Career expats will look down on teachers for largely the same reasons, but also for class reasons.  In Shanghai, all EFL teachers will lie about their jobs to avoid the shame of the teacher stereotype.  
I will admit, teaching EFL in Asia has its good points.  I learned quite a bit while I was doing it and it has given me a rather unique perspective on life.  However, I do regret spending so much time on it.  
EFL is a means to an end.  Its best to keep that end in mind while you are engaged in teaching. The end might be learning a language, starting a business, working on a creative career, or just a travel opportunity.  Loosing sight of why you are doing it and what you are doing next can be disasterous.  Spending one to three years teaching, before moving on, is a good rule of thumb.