538  Sometimes we stare so long at a door that is closing that we see too late the one that is open

649  He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you.

627  When you stare into the abyss the abyss stares back at you.

626  Battle not with monsters, lest ye become a monster, and if you gaze into the abyss, the abyss gazes also into you.

713  In Paris they simply stared when I spoke to them in French; I never did succeed in making those idiots understand their language.