We are not special. Money has been very unpredictable entity in history. In the past, economic thinking was not that developed. There were no alternatives.

Historical fluctuations in inflation: https://en.wikipedia.org/wiki/File:US_Historical_Inflation_A...

Historical interest rates: http://i.imgur.com/i0xit0K.png

More important than store, is predictability. If you know it's going to be 1-5% inflation next 20 years with high probability, life is much easier to plan than if there is high change of huge deflations or inflations.