What is the most difficult/challenging aspect of Teaching?

Although there are many aspects of teaching that seem challenging, the most important and sometimes challenging is getting and keeping students motivated. Keeping a motivated student body can prove a bit difficult because it is an ongoing process.  The students must first see you as someone who cares about their success and someone who is an expert in their field.  Developing a solid rapport with students is only the first step.  The next step is understanding the student body of today. These students demand relevant. practical content delivered in an engaging manner that allows them to quickly learn and apply new information.  Long gone are the days when long lecture classes with no student interaction and input are the norm.  The profession of teaching must constantly hold firm to high expectations and at the same time deliver content in a manner that appeals to this high tech, constantly changing, information driven culture we find ourselves in.

For me the kost difficult challenging aspect of teaching are when the time to licture but the students doesn't want lestining in my lecture something doing when i am licture them also if i want explaining they dont understand it why because they dont lestining to my topic...