Haven't read the whole thread so apologies if it has already been mentioned
I think that most teachers follow the 'reflective practioner' model, which means that you do your best, and then afterwards think about how things went and improve it for next time.
Anytime something goes wrong in lesson, the teacher really needs to take responsibility. Even great kids can act up, and when they do, it is often the fault of the teacher. For example, a poorly planned lesson where the resources don't appear means that the teacher needs to waffle/apoligise/waffle...
Even with truly difficult classes, it is still up to the teacher to take the hit for a bad lesson. There are teachers who can relate to these kids, so there is some hope, and opportunity for lessons. At the end of the day, you can only control your own behaviour, and not the pupils'.
If you have a lot of difficult classes, it is a horrible working environment. What is crucial is to have a supportive team behind you.
I can't hack that environment and am in awe of those who can. I teach in a place where pupils have a generally good attitude and where sanctions are real. I cannot fob off an bad lesson on them - if things go pear-shaped, there is only one person to blame.