Tony Judt:

Evil, above all evil on the scale practiced by Nazi Germany, can never be satisfactorily remembered. The very enormity of the crime renders all memorialisation incomplete. Its inherent implausibility -- the sheer difficulty of conceiving of it in calm retrospect -- opens the door to diminution and even denial. Impossible to remember as it truly was, it is inherently vulnerable to being remembered as it wasn't. Against this challenge memory itself is helpless.

Donald Rumsfeld:

Everything seems amazing, in retrospect.

Arundhati Roy:

To love. To be loved.
To never forget your own insignificance.
To never get used to the unspeakable violence and the vulgar disparity of life around you.
To seek joy in the saddest places.
To pursue beauty to its lair.
To never simplify what is complicated or complicate what is simple.
To respect strength, never power.
Above all, to watch.
To try and understand.
To never look away.
And never, never to forget.