The right thing would be to have 0 change in the value of money as long as the right amount of money exists.

The right maount of money is the amount of money we as normal humans need to work with (buying and selling stuff).

Inflation and deflation are results of too much money or too little money in comparision to the production capability of a society.

If i save today for my retirement and money gets less valuable when i'm retired, i have to give more 'saved' capacity back to get the real capacity (people taking care of me) and if i have more value, the others have to do more for me.

Controlling this is 'work' from experts and is not solved by bitcoin btw.