Hmmm, we'll have to make up a term for this specific symptom of AFMO.  But,
surely, we've all done this. It's clearly a result of mental saturation.

Let's just say that if you see something you like at a Flea, pick it up and
DON'T PUT IT BACK DOWN until you are absolutely certain that you aren't going to
buy it!!! Why? Because I'm right behind you, waiting for you to put it down
without purchasing it, whereupon it becomes fair game!!!

'Nother tip: Don't examine it too closely until you agree on a price!  The price
goes up if the vendor thinks you find the item truly interesting!

John Ruth
Still smarting over losing out on a 19th-Century die plate by stepping away in a
moment of indecision, whereupon another shopper bought it !