Diderot Effect

The term was coined by 18th century French philosopher Denis Diderot who wrote the essay “Regrets on Parting with My Old Dressing Gown.” In his essay, the author receives the gift of a beautiful new "dressing gown," which he loves. However, he soon realizes it makes all of his other things look inferior. So he goes out and buys new things.

Diderot writes: "I was absolute master of my old dressing gown...but I have become a slave to my new one"… "Beware of the contamination of sudden wealth. The poor man may take his ease without thinking of appearances, but the rich man is always under a strain."