I am a true linguist with deep respect for languages, their structure and mentality.
Many people become language teachers simply because they have failed in their other careers. If this is the case, then in my opinion they don’t actually have the right to call themselves teachers.
Ask yourself a simple question: could you be a good teacher of your native language just because you can speak it easily?
I on the other hand have graduated from linguistic studies and I keep challenging myself with various official language exams in order to know precisely what my students need to be prepared for.