Not all scratches are the same. Some scratches are just marks raised above the paint that are left by another object. If the object that rubbed against your car is softer than the car’s paint, it will deposit material on the paint’s surface. That object could be a rubber bumper of the shopping cart, a door of another car, or a wooden post. It can also be tree sap, road tar, glue, goo or various crud.
To distinguish a scratch from a mark, go over it with your fingernail at a 90 degrees angle. This will tell you if it’s gouged into the paint or sitting on top of the surface. It shouldn’t take you more than an hour to repair residue or a scuff marks.