Oddly, young Sherlock reminds me of a school friend, similarly gifted on the violin, and similarly sulky, anti-social, and prone to outraging grown-ups. He was in the Cincinnati Symphony for a while (at quite a young age) and now, last I Googled, is the violin tutor at Choate-Rosemary Hall. I can only assume that his gift for truly inspired rudeness has been well suppressed.

Perhaps Mycroft should have threatened Sherlock with a life teaching ungrateful teenagers to play the violin. That might have scared him. :)