Teachers in my experience have had one of two issues: classroom management, and administrative management. Having a struggling student is troubling, and when that student sees the only positive attention coming his way is from other students when he misbehaves, he will misbehave without regard to consequences. Often the student does not even see consequences as bad! We are always taught about ways to deal with the struggling student, and many of us find ways to do this. It often takes a great deal of effort, and those of us that succeed should be praised! However, for many other teachers, the constant demand for help and attention required by multiple students exceeds what that teacher is able to give, and that, for sure, will be a hit to confidence.
The other realm is a surefire confidence-killer. If the administration of a school is incompetent, inexperienced, or makes self-serving decisions, the powerless teacher will certainly be affected by being put in a position of quitting (and not being able to find a job for some time AND having to deal with a negative reference) or just doing as told and feeling no different than a teenager at McDonalds being told to man the fry machine. Having leaders is necessary to keep cohesiveness at work and keeping everyone accountable. However, when you have a principal who has no experience in your area telling you you're teaching incorrectly, it can get annoying very quickly. The confidence-killer comes when you realize this person is your boss, can tell you what to do regardless of whether or not a decision is right or informed, and makes more than you will as long as you remain a teacher.
Granted, in Texas (where I taught) there are no unions..and I did teach at a charter school. Maybe I brought the administrative problems on myself! ;-)
One reason for a lack of self-confidence is a mis-reading of students' reactions. The first class I ever taught (a small discussion section) included one student who seemed utterly hostile. He seemed to hate the class. I kept him after class one day and asked him if he might want to consider dropping the class since he seemed so unhappy in it. He revealed that in fact he was not unhappy -- just very nervous. He felt that the other students were much more capable than he was and that he could never "hold his own" in discussions with them. I had, in short, completely misread his response to the class. After that discussion, I felt much more at ease in the class, and so did he.
I whole heartedly agree that lack of administrative support is a major factor in teachers losing confidence in themselves. Even the best of students can be trying at times, and there are many who know that their parents will believe any tale they tell, so the teacher has two strikes against him/her from the onset. Administrators tend to be more concerned with low displinary referrals and high passing rates rather than student accountability. These things cause many teachers to feel as if they are fighting a lonely, losing battle.
Having said that, one of the great rewards of teaching is to see a former student some years later when they have matured into responsible adults. When that former student comes up to one and says "remember me," there is a great feeling of satisfaction that one has contributed to the student's success in life. Not all succeed, of course; many end up incarcerated or worse; still the fact that a student's childhood years are a transitory stage and many (if not most) will mature into responsible adults should give heart to those teachers who cannot see the light at the end of the tunnel.
Teacher confidence grows with experience. I remember as a first-year teacher, I was somewhat intimidated by my high school students, some of whom were only six or seven years younger than I. They also recognized my youth and inexperience, but thankfully, few of them tried to take advantage of this situation. I agree with the previous post that puts much of the blame on administrators who refuse to support their teachers 100%. Many teachers also recognize that the slightest disagreement with a student can result in parents and administrators getting involved--a situation that rarely is good for the teacher. Sadly, many students are perfectly willing to blame the teacher for all problems that arise in the classroom instead of taking a good look in the mirror and admitting that they, too, are part of the problem.
A teacher may lack confidence in a day's lesson (or a unit lesson) when the lesson is something the teacher has never done before. With anything new, there is a learning curve for the teacher as well as the students, and the teacher may not be able to anticipate how an activity will go, and therefore is nervous and unsure of how to handle the problems or circumstances that arise. If a teacher has never done a group research web quest before, then he or she may be nervous about how well the students will do and how to handle any unexpected problems. If a teacher hasn't ever team-taught a lesson, then he or she may be unsure of how to handle the interplay between two teachers.
The last paragraph of the previous post expressed exactly what I was going to say. Teachers are people, too, and they have areas in which they feel confident and areas in which they feel not as strong, just like other people. The difficulty arises when teachers are put into situations or assignments that bring their weaknesses to the forefront. Teachers seldom choose to be in these positions, but circumstances sometimes dictate such a placement.
I would have to agree that confidence is lacking when a teacher is not supported or expected to teach a subject which they do not possess a mastery. Also, simple things such as being observed by an administrator or fellow teacher can lower one's confidence.
In the end, teachers are no different than any other person. Most people feel a lack of confidence at some point (or multiple points) in their lives. Teachers are simply held to a different standard based upon the fact that they are responsible for the "future." That fact alone can cause a person's confidence to waiver.
Administrators are mostly to blame for a teacher's lack of confidence. If, as mentioned above, the teacher recognizes that she/he has little or no classroom control, confidence is lost. But, if the administration supports the teacher and disciplines the troublemakers, a teacher can regain control and thus, recover confidence and respect from the students. Just knowing that someone above them supports their efforts instills much confidence in a teacher.
Another issue is the position some teachers are forced into when they have teach outside their area of expertise. As an English teacher, my confidence in the classroom is at its highest. I do not generally experience discipline problems as an experienced teacher. However, in my career i have been expected to teach subjects as diverse as ICT, Geography, and French (I gave up learning French when I was 12). In these situations I did not feel as confident.
Another time I lacked confidence was when there was no support by management when carrying through discipline measures. A student who had brought an air gun to school and fired it in the playground was to be in classes until his discipline meeting. I did not feel safe with this arrangement; as much for my students as for myself. Thankfully, he chose not to attend again.
I am fairly confident that you are going to get a great deal of responses to this one because every teacher is going to have their own take as to why a lack of confidence is present with some teachers. I think that one reason why a lack of confidence is present is because of the demands of classroom management. I am not sure there is one area that is more difficult and one that receives less in way of teacher preparational instruction than classroom management. Teachers are prepared in the realms of curriculum, content development, differentiation, school finances, and administration, but the one basic element that pretty much defines success or failure in a classroom setting is classroom management. It's amazing to think that the most erudite and learned scholar regarding curriculum implementation and instruction can be rendered virtually useless by a group of fifth graders if there is no classroom management skills. The basic tone of the classroom, the focus and harnessing of student attention, as well as the reception to instruction is rooted in classroom management.
It is also in this realm where the greatest lack of confidence emerges. In some sense, it is a logical extrapolation based on the lack of preparedness offered. A teacher can enter the classroom with great ideas about content and instruction, but be rendered useless by the lack of classroom management. Due to the fact that this is not something where much of teacher preparation courses focus, it hits the new teacher in a surprise attack manner. It is disarming to not be able to control a group of students and be rendered pretty much useless in front of the classroom. There is a moment where the teacher who has no control of the classroom, armed with the best of intentions, recognizes their own futility and this is where a lack of confidence emerges. It is difficult to feel comfortable in the instructional setting if one has no control of the classroom setting and here is where the lack of confidence emerges. There can be many locations as to where the lack of confidence can emerge, but I think that the lack of a classroom management setting is a major contributor to this painful and rather uncomfortable experience.
They have fear and also some bad sectors from their teachers also. some time may be a teacher feel financially unsecuerd so he feel himself weak and loss his confidence.