Broken window fallacy
I learned this in business school:
A boy breaks a window.
The townspeople looking on decide that the boy has actually done the community a service because his father will have to pay the town's glazier to replace the broken pane.
The glazier will then spend the extra money on something else, jump-starting the local economy.
The onlookers come to believe that breaking windows stimulates the economy.
The Broken window fallacy theory argues correctly that:
By forcing his father to pay for a window, the boy has reduced his father's disposable income.
His father will not be able to purchase new shoes or some other luxury goods.
Productivity has also decreased, as the time the father spends dealing with the broken window could have been put to better use. Thus, the broken window might help the glazier, but at the same time, it robs other industries and reduces the amount spent on other goods.
Hope this helps, and I just checked a French man Frédéric Bastiat in 1850 created the theory apparently.