The human brain did not evolve for life in a delayed-return environment.
The earliest remains of modern humans, known as Homo sapiens sapiens, are approximately two hundred thousand years old. These were the first humans to have a brain relatively similar to ours. In particular, the neocortex—the newest part of the brain and the region responsible for higher functions like language—was roughly the same size two hundred thousand years ago as today. You are walking around with the same hardware as your Paleolithic ancestors.
Compared to the age of the brain, modern society is incredibly new. It is only recently—during the last 500 years or so—that our society has shifted to a predominantly Delayed Return Environment. The pace of change has increased exponentially compared to prehistoric times. In the last 100 years we have seen the rise of the car, the airplane, the television, the personal computer, the Internet, and Beyonce. Nearly everything that makes up your daily life has been created in a very small window of time.
A lot can happen in 100 years. From the perspective of evolution, however, 100 years is nothing. The modern human brain spent hundreds of thousands of years evolving for one type of environment (immediate returns) and in the blink of an eye the entire environment changed (delayed returns). Your brain was designed to value immediate returns.