How to use the internet successfully
The profound feeling of realizing that everyone, including strangers passing in the street, has a life as complex as one's own, which they are constantly living despite one's personal lack of awareness of it.
In fact, with the right amount of curation, I've found other lives are far more complex than my own. With a little elbow grease and a touch of serendipity, you might discover a world far more vibrant than you would have ever allowed yourself to experience before.
At least, that was true for me whenever I put down the megaphone and stopped yelling at strangers.