Your dashboard already tells you which side the gas tank is on

Pull into an unfamiliar rental car, glance at the fuel gauge, and you'll usually find a tiny fuel pump icon near the low-fuel mark. Look closely: next to it is a small triangular arrow pointing either left or right. That arrow isn't decoration — it points to the side of the car where the fuel door is located. Arrow on the left, tank on the left; arrow on the right, tank on the right.

This simple indicator became common on dashboards starting in the 1980s, precisely to spare drivers the awkward dance of pulling up to a pump on the wrong side. It works on the vast majority of modern cars, so you never have to crane your neck or guess before choosing a pump lane.

The deeper life-hack principle here is that many everyday objects encode hidden affordances — small design cues built to answer a common question you didn't know was being answered. Once you start looking for them (the notch on a measuring tape, the ridges on the 'F' key), you find guidance hiding in plain sight.