do you have a source for that stat about South Koreans being 5 inches taller than North Koreans? Not that I'm doubting you; I just think it's awesome, and want to be able to authoritatively bust it out in conversation.

It comes from Don Oberdorfer's The Two Koreas.

It's true, B+ students are the worst. In most of life, 20% of the population causes 80% of the headaches. In college, those are about evenly divided between B+ and D. (F students are easy, it's hard for them to argue with their fate.)

After watching that diavlog, the burning unsolved question for me was what was outside his window that kept distracting Matthew?

Good diavlog. The pairing of Dan and Matt is a good one: good chemistry, enough difference of opinion to be interesting, but with enough common ground that they can meaningfully engage each other.