I teach for a living during the day--then sometimes teach martial arts at night. As with anything, a job is sometimes a job, no matter how much you like your job--you put on a good show but aren't feeling it that day. As to a change of pace for the instructor--well, that depends on which student has shown up!
Arnis is very interactive--and your arms are going all the time with the sticks. In a regular class I demo. a technique, then begin by working with a student (rotating each time, then using him for the next demo.), then bow out and wander around to look at the other students. Now I'm going nonstop all class. It's more tiring.
It isn't that I don't like teaching classes or don't see it from the student's P.O.V.--but for me it's more work, and if it's not a better-than-average (where paying attention and wanting to learn are concerned) student then it just isn't as much fun as a group dynamic. This is esp. so in an always-partnered art like arnis. If I were judging and correcting kata too it might feel different!
