Sshhh... by David Brin
The story opens with 2 Earth Survey vessels escorting Lentili
starships to Earth. The Lentili are a race of tall, long-lived aliens
who are far more technologically and philosophically advanced than
humans, who have only recently ventured to the stars. While the
Lentili are en route to Earth, Earth President Tridden makes a
planetwide announcement. He reveals that an eminent psychologist has
discovered that the Lentili, for all their power, lack a certain
talent possessed by humans. This talent is apparently rare and almost
unthinkable among galactic races. Tridden will not reveal exactly what
this talent is, but describes it as "something so mundane to us that
few human beings ever bother even thinking about it past the age of
ten!" This talent can wreak "untold psychic harm" among the Lentili
and he asks the people of Earth to join him in making a "great
Tridden asks the human race to remove all mention of this talent from
literature and from daily life.
The last lines of the story are
They walk among us like gods. But we have our revenge.
For the Lentili know Tridden must have been mad. They know there is no
secret talent. We are not sheltering them from some bright truth,
hiding something from them out of pity. Out of love.
They know it.
And yet, every now and then I have seen it. I've seen it! Seen it in
their deep, expressive eyes, each time something new from our
renaissance surprises them, oh, so briefly.
I have seen that glimmer of wonder, of unease. That momentary, fearful
That is when I pity the poor creatures.
Thank God, I can pity them.
It's collected in Otherness among other places.