Textbooks on macroeconomics explain the so-called IS curve and use it to show how the government can boost economic growth in the current year.

Explain why no serious economist would claim that a government can do this successfully every year.

Optimism or pessimism about business conditions and economic growth can also lead to shifts in the IS curve. Describe a case from the real world where economic growth picked up because of more optimism and another case from another country where economic growth declined because of greater pessimism about business conditions and economic growth. Try to be specific and discuss after which events and for what reason optimism or pessimism changed in a big way.