Who knows the weirdest facts?
I think Iruka knows the weirdest facts, simply because he works with small children every day, and I imagine that they are all inclined to tell him about new things that they’ve learnt, which are generally super random and obscure (and totally about dinosaurs, planets, uncommon animals, etc. XD).
He finds a lot of the facts quite interesting, and sometimes can’t wait to tell Kakashi when he gets home. Though sometimes, he doesn’t remember them until they’re going to bed, and he’ll just suddenly be like “Did you know there is a snail that lives deep in the ocean around volcanic vents, and its shell is made of iron?”, and despite how tired he may be, Kakashi will be too curious to ignore Iruka or just leave it at “Huh. Interesting…” or something like that; and they’ll end up talking for hours about it and other interesting things that come to mind.
Kakashi does know all kinds of things, too, but I feel like his brain would be wired more to retain important information like facts relevant to a mission, survival, etc., and all that other stuff he uses in daily life, as opposed to the random things that Iruka has learnt from his students. But in saying that, he does find said facts interesting, and loves asking Iruka about them & discussing the topic, and theories that may develop from the discussion.
What are your thoughts?
But every now and again, the ideas come as passing thoughts; and when they do, I make sure to jot them down, ready for the days that my mind goes blank 