Look before you leap. Think before you act. An ounce of prevention is worth a pound of cure. The English language has no shortage of phrases, which encourage one to evaluate the possible consequences of our actions. But truth be told, this is a nigh impossible task. With each choice we make, we simultaneously create and destroy innumerable possibilities. It's inconceiveable that we could anticipate all of them.
Things get infinitely more complicated when we contemplate human interaction. Even if we lived on a desert island, the actions of people thousands of miles away, could affect the quality of the fish we feed on to survive our solitary existence.
Most of us don't live on a desert island, so things are even more complex. When the web of our choices combine with those of others, they form a structure so complex, that there will always arise an unintended consequence from an innocuous act. And sometimes the consequence will affect others, more than ourselves.