Why do price changes happen so suddenly?

 Communications on the whole planet are almost instantaneous. Everyone from the oil well to the consumer will fill up on fuel if any event creates an expectation of a price increase. Think about the impact of all of the vehicles in a country going from an average of 3/8 of a tank of fuel to 3/4 of a tank. This can be cause of price spikes. Virtually no event will trigger a sudden price drop which could be as sharp as some price increases.