Tommy Harper is the reason I am a Sox fan.
I lived in the shadow of County Stadium in Milwaukee Wisconsin back in the last 60's to 1970. The Seattle Pilots moved to Milwaukee, and I used to pay a dollar to watch some games from the bleacher. (Imagine, I sometimes went alone as a 5th grader!)
Tommy was easily the most exciting player to watch, and he quickly became my favorite player. He was something like the 3rd player ever to hit 30 HRs and steal 30 bases in the same season.
We moved from Milwaukee to Portland, ME in the summer of 1971. In the fall of 1971, he was traded by the Milwaukee Brewers with Patrick Skrable, Lew Krausse and Marty Pattin to the Boston Red Sox for Ken Brett, Billy Conigliaro, Joe Lahoud, Jim Lonborg, Don Pavletich and George Scott.
I switched to the Red Sox that winter and started as a Sox fan in 1972. The rest is history.
(I thought the Brewers were going to win it all (before the Sox) in 1982 vs the Cards. A guy I bet even paid me my "winnings", only to see the cards bounce back from down 3 games to 2 after a bad call.)