Pissing off your spouse is a pertinent new cost of bailing from the concert, not a sunk cost. The ticket price is sunk, because you paid it in the past and can not change it.
If the ticket is fully refundable then it is also not a sunk cost. The land example also has potentially the same issue if the land can be sold for the purchase price. If the land can be sold but at a 20% discount then the sunk cost is only the 20%.
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Pissing off your spouse is a pertinent new cost of bailing from the concert, not a sunk cost. The ticket price is sunk, because you paid it in the past and can not change it.
If the ticket is fully refundable then it is also not a sunk cost. The land example also has potentially the same issue if the land can be sold for the purchase price. If the land can be sold but at a 20% discount then the sunk cost is only the 20%.