I live next to an abandoned building from the Spanish property boom. It's now occupied illegally. Hype's over yet the consequence is staring at me every day. I am sure it'll eventually be knocked down or repurposed yet it'd be better had the misallocation never happened.
I bought a flat in the Spanish property boom. It was empty a while with ~80% of flats in the area vacant, then I had a squatter, now kicked out. Now most of the property is occupied and the Spanish government are bringing in huge restrictions to ease the property shortage. These things go in cycles. The boom and bust isn't very efficient but there you go.