It's actually cheap in relative terms when you consider how much we pay for bottled water by the litre, milk, aftershave by the 100ml, and so on.
Its got to be an expensive operation to get it from the sea bed to the forecourt at the quality we expect.
Yes it hits us hard as we buy so much of it, but profits are higher for chocolate bars at petrol stations than they are for the litre of fuel.
That said, I would still like to see it back to where it was when i passed my test (64p per litre of diesel).