“Caffeinated society is a battlefield where everyone loses,” reads the headline on one of the most recent posts on r/decaf, a subreddit for those who have recently weaned themselves off their daily coffee habit. In the post, the author, who goes by u/fuhgg_, outlines how quitting caffeine is “a hero’s journey” and how those who embark on the process “should feel proud for every minute that you have suffered for this goal.” “Calm salute comrades,” it concludes.

The tone of the post is earnest, sweeping, and dramatic...