If its important and its lacking, TEACH IT.

I don't understand the teacher who complains that his or her students don't do something that is easy to fix.

A good example is the use of the word please.

I can't tell you how many times over the years I have heard a teacher complain about the lack of manners in their students. 

But the absence of many behaviors that constitute manners is not akin to a learning disability or an emotionally troubled child. 

Manners, like many things, are an easy fix.

And they also have to be learned.  

With the application of instruction, consistent role modeling, practice and positive feedback, the use of the word please, for example, is not a difficult behavior to foster and reinforce in a student.  

And being that the person complaining about the absence of the word please is a teacher, wouldn't instruction like this be in his or her wheelhouse anyway?

If a teacher is struggling with a student because he is apathetic, angry, effortless and three years behind his classmates in terms of learning, I understand the occasional complaint.  It doesn't mean that the teacher has given up.  Sometimes it's just healthy to express your frustration.

But to complain about a student who isn't using the word please or doing something that is simple to fix has always seemed a little silly to me.

Perhaps some people are more prone to complaint, but I have always believed in avoiding complaining whenever possible.  So when it comes to easy fixes, I just do my job and keep my mouth shut. 

And I also suspect that despite the persistent belief that kids these days don't have the same level of respect for their elders, teachers two hundred years ago were probably complaining about the same kinds of things.