There can be multiple challenges in the teaching, both with students and with teachers.
Students` motivation, background, age, experiences, friends, life situation and order of precedence can have a positive or negative impact on learning. In some cases, it is not for either (to teacher or student) to push the student towards a better grade if the student have choose to use his/her time to something else. She/he has valued something more important than the one in question. Sometimes the average results is good enough. This is the question, which teachers should ask before the courses. Therefore, teachers can push those students who want to reach the better scores, but they need some support.
The word push can contain negative and positive atmosphere. In this text, I think it is positive word. Almost like support. From here, we can continue to another problem. Unique perspectives. To someone, push (even it is a support to another) can be distressing and mean. At this point, the teacher had to know what to do.
The same things that affects to students learning can affect to teaching. Teachers are also individuals, who have their own thoughts. The difference between teacher and the students is that at the same time the teacher have to teach some detailed topics and follow the atmosphere in the classroom. Teachers should sense the learning levels (tiredness, blank look etc.) from the students. Then the teacher can change the voice volume, topic or take a break from monologue. But! Teachers are not fully responsible for learning. They can help and provide some support and tips, but after all, students have to do the work.
These challenges are just a glimpse of all the factors that affect to learning and teaching. I think that the teachers have a massive role in the classrooms and teaching situations. Teachers can prevent or contribute to the existence of these challenges. However, there are as many ways as there are people.