I was born in Boston and attended Red Sox and Celtics games as a child. Naturally I was a fan of both. Additionally, my son is a college student in Boston and from his Back Bay apartment we can walk to Fenway Park in five minutes. I visit 3-4 times a year and attend Red Sox games whenever I can.
When I was 8 we moved to Texas and I soon became a fan of the Dallas Cowboys, which was 100% mandatory as a resident of the western part of the state. Church (Presbyterian) would start early and finish early whenever the Cowboys were playing a game on the east coast with an 11 a.m. start time. It was said that Texas Stadium had a hole in its roof so God could watch his favorite team play.
My love for the Yankees came about because my dad was a long-time fan and he would regale me with tales of the exploits of Mickey Mantle, Joe DiMaggio, Yogi Berra, Whitey Ford, Billy Martin (off the field), Ryne Duren (humorous stories), Phil Rizzuto, Tom Tresh, Roger Maris, Bobby Richardson, etc.
So yeah, I love the Red Sox AND the Yankees. Crazy, but true.