Phil has a pair of slippers that Claire isn’t too fond of. While they bring private benefits to Phil in the form of comfort and easy jokes, it imposes a cost on Claire. Under the Coase Theorem, we’d suspect that Claire could pay Phil to stop wearing them or Phil could pay Claire to let him keep wearing them, but Claire has instead opted for a creative (and often illegal…) way to dispose of Phil’s possessions that she does not like.
See more: external costs, externalities, negative externalities, subjective value, tastes and preferences
Economics of Modern Family 