I agree with the whole Sox town mentality.
Here's why... the Red Sox fans (even bandwagoners) perennially suffer the 'so close' syndrome of lost love and all that jazz (plus fantasies of curses and New England haunted lakes in Sudbury) but lifelong Celts fans have always had a quiet confidence about their team, even during the '78/'79 time when it was restructuring. Since the impossible dream season of '67, it's always been about the '75 Carlton Fisk home run and '78 Bucky F*-ing Dent, as if anticipation and suffering are akin to being a fan.
I recall the 70s squad of Havlicek, Cowens, and JoJo. Come on, everyone knew that they could win at any time and from '72 to '76 (the Paul Silas era), half the time when one of the big four weren't injured, they did win a title. And really, Cowens quit after that Phoenix series because Silas, his b-ball soulmate wasn't rehired. So all in all, the Bird era was really a continuation of a quiet type of confidence that one's b-ball franchise was the [Brazil-to-soccer] but of [Boston-to-basketball]. The difference being was that Bird attracted more attention, esp from the layperson who'd never watch JoJo White shoot lights out but would rather see it from a blue collar white guy from Indiana. And this extended even beyond New England where really, the Celtics reflected a type of white man, working class ethic. Bird was that and that's why the Celts had unheard of viewership in the 80s. But for the lifelong Celts fans, it was a part of a continuum.