Today I have learned two very important lessons. Firstly, I can't write on blackboards for more than three hours without developing a blister. Second, I can't talk for more than four hours out of every six without developing a serious sore throat.
Obviously, the fact that I am a total wimp is not particularly surprising. On the other hand, it's genuinely interesting to have proved I must spend less than two thirds of my waking life talking. Who would have guessed?