On top of things I could never do, I would have to say Teacher. You would think I would choose something like brain surgeon or nuclear physicist or something like that. Naw! That are things I do not have the ability to do.
On the other hand, I have the ability to teach. Some people even say that I have been successful at teaching people, especially one-on-one. The differences on all of these occasions have been that my “students” have been very willing. They wanted to learn. In some cases, highly motivated. In one case, it was either learn basic algebra or not get into the Marine Corps. I was able to up-train him so that he was able to get his choice of schooling. Needless to say – motivated.
Then why could I not be a teacher? The key word is motivation. I could not teach someone who was not interested in learning. I have no patience for unmotivated people. I have patience for ignorant people but not unmotivated, stupid people. By stupid are those who refuse to learn. Thus, I can not now nor ever be a teacher. Thus those who do and are good at it have my absolute respect.