Medicine asks you to make perfect decisions with imperfect information.

From The Laws of Medicine by Siddhartha Mukherjee, quoting an anonymized surgeon.

It’s easy to make perfect decisions with perfect information. Medicine asks you to make perfect decisions with imperfect information.

Not just medicine.  It is easy to make perfect decisions with perfect knowledge.  Life asks you to make perfect decisions with imperfect information.  Too frequently we do not acknowledge or take into account this reality.  Perhaps even more frequently, we mistake ourselves as being in the first condition when we are actually in the second position.