It made me stop and think about it for a while.

It feels like I learned on a deeper level than if s/he had just explained it.

. . .

But the takeaway here is, I think, not to make us better C programmers. I think the takeaway is that C sucks because it just smiles at esoteric bugs like this. We need to replace it, or forever suffer from crashes and RCEs, et.c.