The title above comes from Hot Fuzz. Having (and forgetting most of) an extensive education in the Latin language makes me pay attention whenever someone starts spouting it.
While doing a little poking around trying to make sure I had it all spelled right, I came across something written by a man named Mortimer J. Adler, an article that includes the Latin phrase used in the movie. I only read part of it, but the final clause of the final sentence below is profound and speaks to me. Perhaps it will speak to you.
“It is necessary to add one critical qualification that must be placed upon the obligations of justice. No one — neither the individual nor society — can be expected to do what, at the time, is impossible; failure to do the impossible is not morally culpable.”