I have found that the busy life does not mean the hectic, crazy, rushing around life. I hate it when my life gets that way and when it does get that way, it is an outward sign that my inner life is in disarray.
I liken my interior life to a spacious room with big windows that are open to the sunlight and to the breeze. When my spiritual house is in order, the room is clean and orderly, sparsely furnished, almost Zen. That is to say that my mind is not cluttered with thoughts, especially obssessive thoughts like resentment, self-pity, thinking about the past, dreading the future. I am in the now, one thought at a time. That is what serenity is, clarity of thought, one thought at a time. Do one thing at a time and when you are finished, pause before going on to another task.
When I am living in Ten and Eleven, free from the past and from the future, living in the right here and now, Twelve happens. I can accomplish many things during the day and not be tired. The world of The Spirit is busy, in the here and now.
Peace,
Jim