What are the positive and negative aspects of taxation?

For negative

But all taxes adversely affect ability to save. Since rich people save more than the poor, progressive rate of taxation reduces savings potentiality. This means low level of investment. Lower rate of investment has a dampening effect on economic growth of a country.

Positive

The positive effects of tax rate cuts on the size of the economy arise because lower tax rates raise the after-tax reward to working, saving, and investing ... But pure rate cuts may also provide positive income (or wealth) effects, which reduce the need to work, save, and invest.