hindsight is 20/20

From the term 20/20 referring to normal visual acuity.

hindsight is 20/20

1. (idiomatic) In hindsight things are obvious that were not obvious from the outset; one is able to evaluate past choices more clearly than at the time of the choice.
   • Another common error dealing with memory is that of "hindsight bias." This is the tendency to exaggerate what could have been anticipated in the past. This is also known as "Monday morning quarter backing" or "hindsight is 20/20" where the "right" decision as to what should have been done appears to be more obvious now than it was in the past. Facing Reality: An Introduction to Philosophy Revised Edition, PhD Joseph Grcic

• twenty-twenty hindsight

• Monday-morning quarterback
• wise after the event