It really doesn’t take that much. Someone lets you in, you give a little gesture of “thanks.” You recognize that someone else did you a favor. It shouldn’t be that hard to do. If we all want society to improve, we must start small. We do this by ensuring everyone waves when another driver extends a courtesy. Wave out the window, up in the rear-view mirror so the driver behind can see, or have a passenger express the gratitude. It’s really not that hard.