When my son started Judo last week, one of my pre-Judo admonitions was not to use it outside of the Dojo. I did this for two reasons - one, I didn't want this to turn him agressive, and two, I know that if he did this one too many times either the principal or his mother would have prompted me to pull him out (Just like my own parents did to me when they felt that I was being too aggressive in my karate class as a kid).
Last night, he turns to me and says "Daddy, I'm sorry, but I didn't listen to you." I was stunned, and I asked what he had done, he informed me that he used O-Goshi on his friend Ben. While I admonished him, I also told him how proud I was of him that he told me this, and finished by explaining to him that part of the trick of learning Judo isn't learning what techniques to use when, but rather when not to use any techniques at all.