At a tangent from an otherwise rather tedious thread, some of us started talking about the history of the English language.
I did a paper called something like History and Structure of the English Language at university and honestly it didn't feel at all like work. The complicated bits have faded into the dusty corners of my brain, but some interesting snippets have remained within easy grasp.
For example, you can see a lot of the geopolitical history of the British Isles in what we now call English. Very basic words like low numbers (two, three) and natural features (sun, land, water) have their roots in our very earliest history and have scarcely changed since the Stone Age. They're also very similar to their equivalents in languages local at the time - northern European languages like Swedish, German, etc.
Place names come in odd clumps too - there are areas in eg Yorkshire and the Highlands which have very Norse names, and often there will be a geographical boundary between Norse place names and Anglo Saxon place names, such as a wide river or mountain ridge.
French came next, with the Normans in the eleventh century. A lot of our food words come from that period, including beef, pork, salmon, etc.
As English eyes looked further and further overseas we started adding more exotic ingredients to our kitchens and words to our vocabularies. Tomatoes, chocolate!
ANYWAY
We're often told that we won't use 90% of what we learn at school or even university, although we don't know which 90%. But I think it's almost always worth learning stuff for its own sake, if only because it's mildly interesting for one day or breaks the ice at one party where you happen to meet your soul mate.
So go on, what snippets have you retained from your years of formal education that are genuinely interesting in their own right? Can be a tiny thing or a major complicated theory, but it must be interesting - at least interesting enough for us to say "well, fancy that".
I'll leave you with this: in Japanese there was no word for "thank you". There were lots of ways of expressing gratitude, but no single expression in the European way. Then the Portuguese came, and suddenly the Japanese were trading with them. They used lots of hand gestures and gradually a kind of pidgin developed to allow them to communicate until there were enough on each side speaking the other's language. But one legacy from that time and that pidgin is a single-word "thank you" in Japanese: arigato. Which you'll notice is remarkably similar to the Portuguese obrigado.