It irks me when someone walks directly ahead of me into a store or a building and lets the door slam right into my face. It annoys me when someone persistently, - and fairly slowly, mind you, - hunkers down in the left lane. It bothers me when someone yawns with their mouth wide open, displaying all their beautiful, or not so beautiful, teeth. Yes, I do care that people care.
Being aware not only that my freedom ends where your's begins, but also extending basic manners, like holding the door open for the person right behind me, are courtesies that smoothen the rough edges and make living together more pleasant. When I'm done passing in the left lane I return to the right lane to leave the left lane free for others who drive faster and want to get past me. When yawning I hold my hand in front of my mouth to spare people sights into the insides of my mouth.
Walking around with earphones even worsens incapsulation into a me-world that lacks consideration for others, or simply demonstrates obliviousness. By being a tiny bit more aware of our surroundings, by caring a tiny bit more about the people around us and acknowledging them, we can make the world a tiny bit of a better place.