Reversibility and the Past Hypothesis (video)
I’ve uploaded another video: https://youtu.be/w07koHD4QEU
TL;DW: It's still weird that entropy is increasing in just one direction (the future). It's weird because the fundamental laws governing the motions of particles are temporally symmetric (there's no asymmetry between + and - directions in time). The traditional arguments for why entropy should increase into the future (starting from a situation of non-trivial order) can also be used to argue that entropy should increase into the past (given a situation of non-trivial order at the present time). But the latter conclusion would be insane. To avoid it, we have to posit that the universe just started out in a state of super-low entropy, 14 billion years ago. No one knows why. Without some explanation, this is super-unlikely.