I believe White Sox and Cubs fans detest each other, as do Red Sox and Yankees. I remember reading tourist advice for Boston that said don't wear a Yankees cap or shirt when visiting. Sounds like it could get ugly there.
I am a Red Sox fan. I live in Brooklyn and I work in Manhattan. I wear a Red Sox cap or shirt all the time. Wore a Red Sox polo to work in Monday after the Sox swept a three game series over the weekend. No trouble.
Once leaving Yankee Stadium after the Yanks beat the Sox on Opening Day the Yankee fans were chanting “BOSTON SUCKS” and I felt slightly worried but not in real danger.
Look at any photo or video of a Sox - Yanks game. You will see the colors mixed in the stands. You might get a nasty comment or maybe beer poured on your head but most likely good natured stick or no react at all.
There is no cordon from the train station to the stadium to seat all the away fans together behind multiple rows of stewards for their protection. There just isn’t the same kind of almost tribal feeling with a history of violence in the backdrop. There is no singing, there is no such thing as banning guys in uniform shirts from bars because fights might break out. Not to stereotype English fans for the history of aggro or take a high road, we’re Americans, we can’t go a week without shooting up a grocery store or attacking the Capitol FFS, but for good or ill our sports affiliations are not our clans.
An American fan would be baffled to watch the Goodison year end tribute to people who passed away in the year, with ordinary supporters mixed in with former players, coaches, etc. They’re all Blues, or Evertonians, of stature, whether it’s a man who played for the club or just a housewife or teacher who sat in the Gwladys for 40 years. The Chicago Bulls don’t consider some guy who owned season tickets and worked at a auto plant to be a “Bull” on a footing with Michael Jordan, a member of the same clan. Just doesn’t compute.
My first exposure was as a student in London in 1989 or ‘90, unwittingly going to meet a friend in what I didn’t realize was the area near the old White Hart Lane, right around the time that a Spurs-Arsenal game was getting out. I had no clue what was on but I was overwhelmed and genuinely scared. And as much as an American might love his team (especially his college team in some parts of the country) we just don’t have that.