Admit it, no matter how many years you've been driving your car, you still run through a half-second "wait, which side is my gas tank on?" scenario every time you pull into a 7-Eleven to fill up. And let's say you're driving someone else's car, or renting, and you want to do the courteous thing and top it off with fuel. How do you know where the fuel door is? You can try sticking your head halfway out the window for visual confirmation, or you can look like an idiot and turn the car around if you guess wrong.
There's one embarrassingly simple trick you probably don't know about that tells you which side of the pump to park on.