Why is zero unemployment and zero inflation not ideal for the economy?

Zero unemployment and zero inflation is not good fpr the economy because inflation is important to keep the economy running. economis t call this sustainable inflation. when there is an inflation, you know that the price will rise in the future. your money is more valuable now since the price is lower then the future thus you sped noe instead of saving. this keeps the economy running.

If unmeployment were zero that would mean no new business could start, no existing business could expand and no one is entering the labor force. shortage of labor like this would increase the wage as the existing business have to compete for the labors and if wage sgoes up then prices goes up as well: inflation.