What's the greatest extent (as in the most amount of time) to which you've eaten something past its expiration date with the food still being enjoyable?
In 2011 I was in an unfamiliar kitchen and had some porridge in the morning. I put some ground cinnamon on it that was in the cupboard and noticed that it was particularly good cinnamon, much more flavoursome than I was used to. I looked at the bottle again and it was the same brand I always use myself at home so I didn't see why it should be so much better but I noticed that the although pretty similar the labelling seemed subtly different than I was used to. I looked at the expiry, it expired in 1986 and the label was different because they'd updated the design since. I don't know why the 25 hear old cinnamon seemed to taste so extra good, I would have thought that if it wasn't somehow rotten and sloiled it'd at least have lost basically all its potency but somehow it was super nice. I even had extra after this discovery.
Yeh it was Masterfoods ground cinnamon if I recall. It really defies intuition because things like nice aromatic spices should get progressively weaker flavoured over time. I feel compelled to say this may have been a freak occurrence and it's probably unwise to seek out 25 year old spice.
I did learn of this difference many years later. To me the Ceylon kind is a nicer, though perhaps less strong a flavour and seemed more like whatever my brain has decided "cinnamony" should taste like, but cassia will give you a more obvious punch even if not quite as delicious. I wonder if at some point Masterfoods switched from Ceylon to Cassia.