It occurs to me that these courses have been teaching what might (should?) be considered a naive view of memory; you show me a traditional cyclic data structure and I'll show you a concurrency bug. I suppose that's fine in 1978 when no one imagined they'd be dealing with multi-core microcontrollers, but today, when you find yourself using a "systems" language for non-toy work and you reach for a tool as sharp as a raw pointer, those naive data structures are frequently (usually?) inadequate.