The actual money spent on petrol is not just the amount/litre. It includes the following also. It is clear that an increase in the cost petrol has a manifold effect.
1. Time spent on the commute to and from the petrol pump.
2. Petrol spent on the commute to and from the petrol pump.
3. Time spent in the queue for petrol
4. Transaction charges paid to the credit card company
5. If you get into a fight while getting petrol you have to bear the emotional, physical and material damages
6. Money spent on the relieving the headache after going through all this
7. Even if you can afford to get the tank full every time it still means more number of trips to the petrol pump