Suppose that in our country we import woolen sweaters from country A, and the sweaters sell for $25.
The local sweater industry petitions the government to impose, say, a $5 tariff (duty) on the imported sweaters. They argue that they cannot produce woolen sweaters for $25 and need this tariff in order to compete with country A. So, the government imposes a tariff.
As a result, the local sweater industry is able to employ many people. However, the consumers now pay $30 for the same quality sweater. The consumers no longer have that $5 to spend on other things. Thus the local sweater industry thrives, but a hundred other industries shrink.
You can see the sweater employees going to and from the factory each day, and you think, “The tariff was a good idea, it has given employment to people in our country.” But you don’t see the hundred other industries that have shrunk and all the lost jobs from that.
— Extracted from Economics in One Lesson by Henry Hazlitt
We see this cognitive error recurring over and over: humans focusing on what they can immediately see, and failing to consider those things that are not immediately or easily visible. See Cognitive error: acting on only what is immediately visible