Monads are a weird infohazard. They are very simple, but anomalously challenging to grasp, so once you grasp them and realize how simple they are, you feel compelled to write something explaining them, targeted at yourself five minutes before you figured them out.
This does work, in that if you read enough of these blog posts you can also figure it out, but it’s not pedagogically efficient.
Pointers are probably in the same category (ha). Notoriously difficult to grasp as a beginner, notoriously difficult to understand why they're difficult to grasp after you "get it", and rife with subpar analogies like "pointers are like the numbers on your house".
This does work, in that if you read enough of these blog posts you can also figure it out, but it’s not pedagogically efficient.