Ever have one of those days when you just feel like garbage? A blah day?
What did you eat the day before? What physical activity do you (not) do? How was your state of mind?
There is a direct relationship between how you treat yourself and how you feel. Sometimes it's not instant, but it's there. The next time you think of doing something (or not doing something) because you don't think it makes a difference in the whole scheme of things....think again.
Did you ever hear about the butterfly effect? "The concept of the butterfly effect is frequently referred to in popular culture in terms of the novelty of a minor change in circumstances causing a large change in outcome." - wikipedia
So the butterfly flapping it's wings (or the grouchy office worker snapping at a co-worker and eating a donut) can affect the incidence and impact of a tornado across the world (or the state of wellness of the office workers and everyone surrounding him/her).