Are we still sharing stories of how we picked our teams? My path came via the path of two other friends', all of which might be instructive:
1. One friend began rooting for Man U. in the late 90s/early 00s because of Roy Keane -- his family had come from the same part of Cork as Keane. (He's also a huge Red Sox fan who somehow talked his way out of rooting for the Yankees of British football. But whatever.)
2. After that first friend started buying FIFA every year in 2001 or 2002, his roommate picked Arsenal to follow for a couple of reasons. First, because he felt the narrative of Arsenal around that time felt similar to the story of the Red Sox if the Sox finally made it to the promised land. Mainly from the book Fever Pitch -- sadly, we all know that he wasn't the only one who saw the parallels there. The second reason was because the Gunners were the only other five-star EPL team in FIFA, and he wanted a shot to beat his roommate in their nightly sessions.
3. Which led to me having to pick a team when I was over there so I could play as well. I wanted to keep it in England, and also wanted a high-enough ranked team to be able to hang in the matches. The 4 and 4.5 star teams that year were, if I recall correctly: Newcastle, Chelsea, Leeds, and Liverpool. "Hey, the Beatles are from Liverpool. I like the Beatles. Plus they got a bunch of Irish there too."
Based on that thought process a dozen years ago, I've ended up purchasing a bunch of kit tops, seen the team play in North America twice, and toured Anfield during my one visit to England. It's nice they now have a Red Sox connection. It's less nice that they missed out on the title this year and that their best player has a Marv Albert problem. But it's been a fun ride, and I'll always have a very long lunch break in 2005 to look back on and smile.
edit: So, yeah...these things can just happen. It's easy, especially for those of us who grew up in a sports market with teams from all four main North American leagues, to assume that fandom has to come from childhood, bestowed upon you by geographic proximity and/or family lineage. But when dealing with new-to-you sports and faraway leagues, sometimes it's random serendipity that gets you hooked on some laundry.