Casey presents some optimizations that seem intuitive and they work correctly for determining separation. However, when computing distance and closest points there are some cases which should not be skipped.

True story. I got burned out from my last job. My mental health took a dive and performance slipped. I was fired for "Poor attitude" at work. Like no shit Sherlock, you didn't give me any help and gave me the work of 3 people to do. That was 6 months ago and im still mentally cooked.