I have taught all grades from K - 12, to graduate school. I find the latter the most rewarding. I am able to be more myself. Perhaps it is because of the commonality of age in most cases. But more so, we share life experiences.
I am always prepared, sometimes over prepared because I want to be sure the students are getting what is being presented. I usually have content left over which helps with the next session. Sometimes, I feel pressed to get it all in, and have to refrain from trying to squeeze stuff in. What I have learned to do is keep tabs on the time and eliminate portions of the content that may not be essential. However, I think everything is essential and have learned to include that in the next session. This has helped to ease my anxiety and not stress students out. They seem to pick on things without our realizing it.