I would like to ask you for sort of a second opinion on one thing that happened to me earlier today.
Since January I have been conducting short lessons for my former high school's maths and physics clubs. It's if not a tradition then at least a customary thing to do where the people who graduated will come back and share what they have learned. So far I gave six presentations on various mathematical concepts and four as a pure prep for the Physics Olympiad. It's never obligatory for students and happens with both consent and approval of teachers and principal. A pretty nice arrangement, right?
Apparently not when I am involved. Few hours ago I had a short discussion via email with the principal that boils down to "we don't really want you to do any more lessons" with some of the least supported by evidence reasons I've seen this side of "we need to make more ice cubes to combat global warming". Apparently, I'm always late and there were numerous claims that students don't want me as a speaker on top of it. However!
1. I was never late. Not a single f-ing time. I'm one of those annoying people who will somehow manage to be on time even if you will change the time and location at the last minute. I once ran six kilometres for my doctor's appointment because detours made any kind of commute almost impossible in the area (edit: and still managed to get punctual). So that's a lie and they (should) know it.
2. While I'm hardly the most sociable person, I actually feel really, really, good in a role of lecturer. I know how to sprinkle the topic with something lighter to keep the attention, make my audience interact as much as possible with me by posing intermediate questions or problems… Suffices to say that I got my past physics teacher to utter the highest compliment I've ever heard from him ("You did a good job", the guy is almost impossible to impress and it showed on our grades :P). My lessons were always followed by a lengthy Q&A that once managed to last almost as long as the presentation itself. Students also seemed to like it. I think that I'm becoming friends with a few of them* and I can't recall being ever faced with "oh, not this guy again" reactions. I actually got a question about my next lesson being cancelled from one of them while I'm writing this post, so I'm less and less inclined to believe that it came from students.
Obviously, you have only one side of the story. Regardless, do any of you have any good idea why I would be rejected? Feel free to ask questions or just throw ideas around.
*) In case this would ring any warning bells: I'm not even nineteen yet and there are actually a few senior students there who are older than I am. This is not the case of twenty/thirty-something being all chummy with a bunch of high school students or similar creepy stuff. Also, nothing about that was ever said and I even asked if this is about my age.
keifermiller suggested something about inane office politics. I suspect that there is something that you don't know. That something might have nothing to do with you. Probably some parent phoned the principal complaining about something.
Did the principal attend any of the classes ever?
It sounds like your past physics teacher attended one of your classes and thought you did good. He sounds like not the warmest guy - but I'd strongly consider asking him. There are various ways to approach him, including saying that you very much enjoyed giving the short lessons and would like some mentoring on how to do it better. Share the good feedback from the students, but say you wish you knew why you were asked not to come back.
Also, who is the teacher in charge of the Math and Physics Club. Who did you work with scheduling your short lessons - the principal or someone else?
In conclusion: there is something you don't know. You may never know it -- but I hope you continue your enthusiasm for teaching. It might be a calling. Don't let the bastards grind you down.