With inflation money becomes less valuable so costs go up. Government benefits from inflation, it's a tax that doesn't need legislation. They can continue to spend without having to pass tax increases and receive an increase in revenue from higher wages . The citizen looses because the money they earned has lost value in purchasing power and they are penalized for saving.
Inflation can be very damaging for a number of reasons. First, people may be left worse off if prices rise faster than their incomes. Second, inflation can reduce the value of an investment if the returns prove insufficient to compensate them for inflation. Deflation is a decrease in the general price level over a period of time. Deflation is the opposite of inflation. For economists especially, the term has been and is sometimes used to refer to a decrease in the size of the money supply (as a proximate cause of the decrease in the general price level). The latter is now more often referred to as a 'contraction' of the money supply. During deflation the demand for liquidity goes up, in preference to goods or interest. During deflation the purchasing power of money increases. Deflation is considered a problem in a modern economy because of the potential of a deflationary spiral and its association with the Great Depression, although not all episodes of deflation correspond to periods of poor economic growth historically. In economic theory deflation is a general reduction in the level of prices, or of the prices of an entire kind of asset or commodity. Deflation should not be confused with temporarily falling prices; instead, it is a sustained fall in general prices.

Amacher, R., Pate, J., (2012). Principles of Macroeconomics. San Diego, California: Bridgepoint Education,