I was struck, however, by the tone of uplift that resonated throughout my friends’ responses to the article. Those I spoke to gave a variety of reasons to explain why they’d shared the piece, from an interest in Sacks’ scientific work to the article’s resonance with their own artistic endeavors. Despite their differences, the language with which they introduced the article was strikingly similar. Only a few referred to it as sad, though I imagine many of them thought it was. Instead, they spoke of it as “inspiring,” “beautiful,” and “moving.” I suspect they were referring primarily to the essay’s closing paragraphs, paragraphs that many of them also quoted, in which Sacks speaks of his gratitude for the life he has lived, and of his happiness at loving and being loved.

How many of my friends would have shared the story if Sacks had failed to take that final turn, if he had described the cells multiplying within, but not his love for the world without? To be clear, I would never fault people for celebrating Sacks’ essay—it is just as inspiring, beautiful, and moving as they say. Nevertheless, the article’s popularity speaks to a troubling trend: Facebook’s culture of the like is actively making it harder to express negative thoughts and feelings.

That's a good point. The language of Facebook encourages positive emotions and discourages sadness.