Gross Domestic Product is the 'market value' of all 'officially recognized' goods and services. For example, rescuing a Lady Bird from horrible death by kitchen sink is not an 'officially recognized' good or service. 'Market value' is the price of a good or service under the conditions of a competitive auction.
Then when Gross Domestic Product shrinks, I could say, 'yippee, we're reducing consumption and there'll be something for those who come after us.' But, instead, I've been advised to think of it as a loaf of bread, up on the auction block, it's price determined by who wants it most.