Deflation
Deflation occurs when the inflation rate falls below 0% (a negative inflation rate). It is the opposite to inflation but is to not be confused with disinflation which is the slow down of inflation. Deflation can be/is caused by job loss, lower interest in purchasing in goods and services, low income, etc. All these things are extremely dangerous to the economy because it poses a potential threat to the economic system in means of system crashing and a depression happening. This is especially bad if it happens in our day and age. Everything runs around businesses and corporations working smoothly and efficiently. If some big brand company wavered slightly then it could cause mass distraught to a lot of people especially if they share in stocks or have any other relationship with the company. However, deflation almost has a menstrual cycle per-say in means of coming regularly and at the worst possible time. (But then again what would be a 'good time' for the economy to crash?) By doing a little research and finding out some specific information it isn't wrong to say that no matter how 'well' the economy is doing someday it will crash again bringing mayhem with it. However, personally being a pessimistic person is a major drag so it is better to wait and see what will happen instead of throwing a life away in fear of when it does. (In no means does that mean to not prepare a bit for it. It is just simply stating to not waste the precious life that is your own.)