Remember summer? Long, balmy evenings, sand and surf, that feeling of thong rubber between your toes. And petrol prices dropping below $1 a litre. It was glorious. But, oh! So brief. No sooner had you blinked than you were back in the office, it was raining, and filling up cost $1.40 a litre. What happened? Every day we hear more about the global oil market taking an express elevator to the basement.