First (before I forget), Barb - I LOVE your certification!
I am a certified teacher - completed a masters level program and took the Praxis exams. I taught in the PS classroom. I was a good teacher and not just bragging on myself - I really was. The Director of Schools for our system called me personally upon learning of my resignation and asked if there was anything they could do to keep me.
I said that she could not fix what was broken. And that was and is a true statement.
I loved being in the classroom and I truly cared about the kids - even the "bad" ones. It is the "system" that is broken and it was the "system" that broke me of teaching in PS.
The education program I completed did not teach me any subject matter at all. It was about public relations (not kidding), handling diversity, special needs, creating individualized lesson plans and unit plans, some child psychology (very light), etc.
At an In-Service meeting, our state's Secretary of Education spoke and made the comment that a Harvard professor with a Ph.D. in physics would not be "qualified" to teach science in the public school system because of the *strange [my word not hers] certification requirements.
Certification, I know, is not primarily about subject matter expertise, it truly is about how to handle rather large groups of same aged kids - plus some other nonsense.
About disruptive kids: I had very little problems with that even with high schoolers. Perhaps that I am male had a little bit to do with that plus I taught in a relatively good school system.
Most of my disruptions came from outside the classroom and were not caused by kids.
I have (nearly) as much empathy for teachers as I do for students.
If you know a good teacher, show them some extra kindness and appreciation. They are a blessing to the students they teach and they have to live within and do their best to overcome a broken system too.