@whitequark Appnotes were written for engineers who just wanted to get something done and move on, which was a wonderful way of making them much more concise. Like you I largely zoned out in my control systems class because I couldn't see the connection between what they were talking about and what it did. Rue MacNohr on twitter taught themselves PID and their experience was interesting to me as an autodidact. Living in a ewaste recycle facility gave them an endless supply of parts to play with.
Tangentially related, on the off chance: do you maybe have recommendations on where to read about thermoregulation? I was wondering whether any of the mechanisms can affect sides of body unequally. I've found some neurology textbooks that implied that the answer is no, but were describing everything in a way that is slightly alien for me.