Repetition and insanity... the foolish or the wise?

It is often said, and I will paraphrase this quite horribly I am sure, that insanity is when a person repeats the same thing over and over expecting to somehow obtain a different result.  However, and this might indicate my own level of insanity to some degree, I tend to think that this overlooks the value of practice.  Just ask any musician who has practiced scales.  Many have certainly delved into the realm of insanity during personal displays of such rote repetition, yet many have emerged from amidst it all carrying harmonious affluence of skill, far more capable of touching the beauty within than every before.  Perhaps merely describing it truly confirms my pointed notions of personally questionable sanity with immaculate clarity.  Maybe it's just fun to run rampantly verbose... an exercise of sanity and mental challenge in itself.