Over the last year, I've started teaching far more youth classes than in the past. As I've gotten a little more comfortable with the format and expectations of younger students, my attitude has relaxed significantly and I find myself far more at ease with the class.
Before this endeavor, I was teaching classes at the University level, almost exclusively to kids in their 20s. A far different experience as you might imagine. Physically, the college students are able to endure more, can be stretched physically and mentally, and provide a great deal of challenges for a teacher who continues to get older while students (seemingly) stay the same age.
A few months ago, at a demo for a Scout group, I brought a few of the University students to assist, and many of them felt as though I had a split personality. This joking, fun instructor who was setting kids at ease and sharing this art was very different from the person who would work them over for 2 hours.
The truth is, I enjoy teaching adults and children for different reasons. Both classes are very enjoyable for me, but they require far different skills, different goals and ambitions.
Kids classes, you spend a great deal of time keeping them from fidgeting, talking out of turn, handling restroom issues, etc.
Adults classes are... well, actually about the same in many ways. :)