Unemployment is by far one of the worst things for the economy. Unemployment makes it so less people are bringing in money into their homes. That decrease in money is lowering the amount of money being spent back into the economy. In order to help the economy, we need to work on getting the unemployment rate as low as possible.
If a larger portion of a country's population is unemployed, it means they are not paying any taxes. No taxes mean a huge hit to government revenue. Additionally, if there are unemployment assistance programs in place, these individuals are now a financial burden on the economy. The unemployment rate of a country is almost a direct reflection of how the economy is doing.