Here we enter the second sphere associated with training, namely the talent of the trainer. Unfortunately, I repeat, unfortunately, you cannot learn this talent. You can graduate from the renowned instructional courses, have excellent detailed knowledge of the subjects to be lectured, but unfortunately you will not be a good instructor. The fact that your business card says instructor, trainer or lecturer means nothing. Skills of conducting trainings are largely innate and you just have to like doing this.

Everyone would like to be an excellent speaker. Nothing gives more satisfaction than the fact that students come to the course only because it is run by a well-known, well-liked and competent instructor. On the other hand, a good lecturer is the one who can perfectly cope with "hyperactive" students, and also  "drift" in such a way that others will not know about.

No one can know everything. I'm not saying this to put the instructors in a bad light, but to make everyone realize that the lecturer is also a human. He also has unreliable memory and can sometimes be wrong.

Contrary to general opinion, it is a very hard and exhausting job. You need to be focused throughout the whole course. Actually, you stay with students for several days, often making friends and solving their problems even during breaks. Sometimes, when the problem is very difficult to solve, the instructor can spend half the night over the solution, to come to the classroom again in the morning and give them his own thoughts and present the solution.

It must be remembered that people who attend such specialized courses are adults, they mostly have very technical education and can catch every, even the smallest error in logical reasoning.