I don't think there will be any more "to the moon" moments in near future as the volume is increasing and there would need to be a much larger inflow of fiat than in the last bubbles, but that shouldn't be viewed as a problem unless you are a wannabe "get rich quick" speculator.
Its okay with overstock! imagine if tomorrow amazon and ebay does that then wont it make a huge impact!
Maybe on the short term, but if more people are at the same time getting into BTC and using it to do their shopping then another balance will be reached between buyers and sellers. It's just basic offer and demand.
The $1200 maximum of BTC was artificially pumped and this correction was to be expected. Do you imagine such a pump on any major currency pair like USD/EUR or GBP/JPY? There isn't enough money in the world to do something like that! As volume increases, pump&dumps are less effective (since they require more cash) and the exchange rate becomes more stable.