I was trying to make electrical contacts that didn't dissolve within minutes when charged with a little bit of sweat on them.

Learned about HEAs (can't remember where), saw some fantastic material properties (rather high yield strengths, solid elastic modulus), and was pleasantly surprised at how much electrolytic corrosion they could resist.

Then one of our money people got a quote from the vendor to see how much it would cost to put it in our product, laughed, and said, "Back to the drawing board you go!" I think it was something like 20x more expensive than a copper alloy contact.

And while you're at it, #2