Gas is one of those things I have no control over. If it's expensive I have to pay, if it's cheap I have to pay. I'm dependent, and in a city like Los Angeles the alternative is impossible. They raised the price of public transport to a point where it is not even convenient.
So when I go to the gas station and it's cheap I'm happy. I fill it up and have a smile on my face. Am I doing it wrong?
It may be bad if you're in an energy-intensive business that's just made investments in reducing its fuel costs, because now the payoff for those investments is worse.
The US was just starting to transition to an oil exporter due to unconventional oil, but now the price has collapsed the boom in North Dakota etc goes away.
In the more general case, rapid price swings cause trouble all round (they make it hard for everyone to plan) even when the price adjustment is "correct". For the economy as a whole, low prices are better than high prices, but a stable price would be better than a volatile price even if the volatile average price was lower.