The problem with the middle is that it prevents you from making extraordinary time commitments to anything. In your effort to attend to all things, everything gets shortchanged and nothing gets its due.
-Gary Keller, with Jay Papasan, pg 75, The One Thing
The One Thing has quite a number of interesting concepts interlaced in its pages. I never really questioned the idea of a balanced life — because it seems intuitive. But I can see his point that if you are always trying to stay balanced, he makes it difficult to achieve at higher levels in a single area, where additional time is required.
Interestingly, he starts his book with a Russian Proverb: if you chase two rabbits, you will not catch either one.