Let’s start with something easy… I’ve come to understand the significance of having your wedding ring on. Yes, I’ve known the definition of what a wedding ring is for a long time, but only recently have I discovered that it’s an extremely reference guide to tell someone that “yes, you’re married” without exchanging a single word. I bet it saves a lot of people a lot of embarrassment! And silly as it is, nobody ever spelled these things out, so I didn’t come to this realization until I’ve started to actively look for potential partners.
By extension, that makes explaining the anomaly of having an extravagant engagement ring obvious: since the couple is not officially married, the ring is basically a giant “stay off my woman” sign.
There’s just so many of these little things that nobody ever bothers to write down, that when you finally had it figured out you’d look at your younger self and lament about how naive you really were. As far as book knowledge is concerned, you do absorb a ton between 13 and 21, and it’s easy to think you have the world figured out… then you grow older and you pick up on all these inconsequential things that wasn’t explained, can’t bother to be explained, never written down, that people simply “get” as they age. I suppose those kinds of hidden knowledge is what people call “maturity”.
Maybe someday, somebody will actually bother to write all these things down, and we’d have people truly full of adult wisdom before the age of 21. I don’t know though… there’s something about learning by experience that really makes the knowledge permanent and pliable. Some things about life simply can’t be taught.