I'm vaccinated, and generally not too worried about me, but I also think it's possible that I could catch and transmit it to someone who isn't, so I have to be careful for the sake of others. Again, the odds are much smaller than if I wasn't vaccinated. If everyone else is also vaccinated, I wouldn't really have anyone to transmit it to, and thus the collective anxiety for those of us who care about the well being of others would go down.
I'm amazed and disheartened by people who walk up to strangers and cough in their face. My daughter works in retail and has had it happen to her a number of times.