i think this song is about people who are hidden gems that we never notice, we "tend to walk right past them". They're not like most other people, they "hide from the world", while everyone else finds themselves drawn to people who put themselves out more. "Strangers kinder than our friends" might talk about those "diamonds in the dark" that stand out so much, even at a first interaction, compared those who are in plain view of everybody in terms of valuable personality.
i think this song is about people who are hidden gems that we never notice, we "tend to walk right past them". They're not like most other people, they "hide from the world", while everyone else finds themselves drawn to people who put themselves out more. "Strangers kinder than our friends" might talk about those "diamonds in the dark" that stand out so much, even at a first interaction, compared those who are in plain view of everybody in terms of valuable personality.