I mildly follow the Red Sox, but it is NEVER the center of my social life. I was a huge fan as a young teen (went to a lot of games and sat in the bleachers). My interest has waned since I started doing my own sports like cycling, hiking, etc. I don't even know who half the new players are, now. Watching cycling is fun, because I can relate to it, but if I never watched a race on TV or on line again, it wouldn't be the end of the world. I abhor football, basketball, and especially hockey. Thankfully, even my "regular" friends aren't huge fans, but they do go to games and watch on TV some of the time.
My son has a new job where he is opening an office of a company based in SF. He told me that he immediately was sent to deal with a long time client here in the Boston area, as they need a "New Englander to deal with them." He told me he has to brush up on the local sports scene to converse with these people...