Like in every profession there are the good and there are the bad. A good teacher may have stress yes, because they care and want every kid to succeed. My sisters, father and mother were and are that way. Most of their peers i know are in it for the money and golden pension. They brag about what they have all the time. A teacher should be compensated based on performance and those whom fail should be let go, instead of being protected by the union and moved to another school.
A masters degree does not automatically mean you are a good teacher. The teachers whom made the most difference in my life were shop teachers. You know the teacher whom worked in the industry, knew what worked and didn't work! The ones that had real world experience. I have always said university is for theorists and college is for realist.
I also remember my grade nine year with a teacher whom had a doctorate in math. I was near failing in here class up until she got sick just before mid exams and had to be replaced. Long behold the replacement teacher whom was a former electrician, and switched jobs mid way through his career was able to actually teach and I brought my near failing grade up to an honours grade. My grade nine year was the only year i had less than 90% in math. Was it me or the teacher???