> The supply chain is selectively fraying.

I went shopping for avocados, Peet's Breakfast Blend coffee, shallots, spinach and tomatoes.   Peet's was on the list because my Amazon order for it says "we're sorry, but you'll receive it...whenever."  I scored first class avocados, shallots and spinach at my first stop (WinCo).  I hit 2 Wal*Marts, a Trader Joe's and Target in an attempt to get the other two items. 

I had to substitute from what I wanted in both cases.