The Diderot Effect: Why Buying One Thing Turns Into Ten

The Diderot effect is a phenomenon that occurs when acquiring a new possession leads to a spiral of consumption that results in the acquisition of even more possessions. In other words, buying something new can cause a chain reaction leading to one buying more and more things. Each new item makes one feel like one needs other things to go with it or to keep up with it.

- Wikipedia

Examples:

• You buy a fancy new couch → now your old coffee table looks out of place → so you get a new rug, pillows, lamp… boom, you have a living room makeover.
• You switch to a nice watch → now your wardrobe feels too casual → you buy some nicer shoes and a shirt.