There is a thing about which today I made a doctor appointment for it, which fits in all three categories.
A. What I can control
Efforts I make to do something about my defective neurological, endocrine, musculoskeletal, and immune systems
B. What I can influence
My defective neurological, endocrine, musculoskeletal, and immune systems
C. What I can not control
My defective neurological, endocrine, musculoskeletal, and immune systems
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"There are a thousand things that can happen when you go light a rocket engine, and only one of them is good."
Tom Mueller of SpaceX, in Air and Space, Jan. 2011