Nurses of my generation were taught to be obsessed with input and output. We kept meticulous I&O sheets for our hospitalized patients. This curious form of accounting was often perceived as an invasion of privacy by patients unaccustomed to anyone being fascinated by their diet and excretions. As a young man from a rather formal upbringing, it took some getting used to: "So, Mrs. Jones, did you urinate recently? And did you measure it? Oh, you saved it in a bed pan. How nice." Plain speaking comes easily. perhaps too easily, after years of these conversations.
This accounting spilled over into my personal life. My own diet and hydration became areas of daily scientific experimentation and observation. Since I worked night shifts for many years, it was not a boring process. The body goes through a lot when its diurnal rhythms are intentionally altered. If you doubt this, try eating pepperoni pizza with Diet Coke at 3 AM when cold sober. My regulation of diet and hydration made working nights tolerable for me. This enabled me to take on a second job during daylight.
My study of Buddhism, which began in college, accelerated in my 30's. Input and output took on another level of meaning in my life. The Japanese Buddhist concept of esho funi impressed me. Rather than seeing myself as living linearly with sequential input (stimulus) and output (reaction), I began seeing myself as living more like a fish, swimming in time and space. Input mixes with output. Output becomes input which becomes output. More fluid and dynamic. Understanding that much of my life's input and output is unconscious, while accepting that even unconscious input and output have effects with which I must live responsibly.
The more clearly I grasp this concept, the more aware I become that the environmental ocean around me is filled with those who are not committed in any way to their environment or even the quality of their own lives. This adds another dimension to my consciousness...a dimension of caution in every day life. This dimension of caution is practiced. After certain events in my life, since I awoke to this awareness, I have felt like a turtle swimming in a shark tank.
It takes practice to remain optimistic with this wakefulness. I am not talking about the inane optimism of the ignorant or religiously deluded. My optimism is based in a belief that I am living one animal life in a vast Universe to the best of my ability. I am living in what I see as my own truth. I am living without presumed antipathy to any other specific being. I am consciously avoiding poisonous input from my environment. I am consciously avoiding poisonous behavior toward my environment within the best of my abilities.
This form of optimism is based in optimizing my life experience responsibly within my environment. It isn't a personality trait. It is hard work. I was fortunate to have been raised by one optimistic parent and two optimistic grandparents, in this sense. That gave me a head start. But I believe anyone can start to live in this way with education, practice and a commitment to embrace change.