Can anyone recommend other rabbit hole videos like the parents? It can be in any topic. I love these types of videos that show just how deep things are.
I recommend his video on speedrunning the first level of Quake, including an overview of the importance of Quake to speedrunning as a whole, and an explanation of Quake's movement mechanics that make getting a good time so complex:
[0] - https://www.youtube.com/watch?v=MToTEqoVv3I