Which side of the car does the petrol/gas reside?

How many times have you asked yourself that question? Me, countless times until a few years ago.

I was traveling with a colleague in a rental car and stopped at a petrol station to fill up prior to our arrival at the airport. The same process entailed where I took a 50/50 change on which side the tank was on so I could fill up. This time I got it wrong and cursed in frustration. My colleague calmly told me to look at the petrol gauge inside the car as it tells you which side the tank is on. Hallelujah!

To illustrate (see the arrow pointing to the right side):

This is something that I have never heard anyone mention in Australia. My parents never told me or did any of my friends mention it when filling up various cars. I’m hoping I’m paying things forward here.