I became a fan in 2008. One of my best friends is a football nut, and a RM fan. At that time my exposure came mostly from FIFA, and the first team I played with was Chelsea.
My friend turned me onto Ronaldinho, greatest player in the world at that time, and Henry, for his sublime finishing. And I also found out about this kid named Messi, who is very close to my own age, when Cristiano won the Balon d'Or that year (I believe it was CR, Messi, F. Torres). And I watched some videos of Messi, then found out about Eto'o, then started following Barcelona. I thought the club colors were the best out of all the clubs in the world, and thought that the playstyle (attacking, possession) is aesthetically more pleasing than what any other team were doing.
So, I became a fan of Barcelona. My reasons were largely down to liking the players of the team, and the aesthetic value they represented. As I found out more about Barcelona's history, its philosophies, and essence of being, I became even more of a fan. Those other great players - Xavi, Iniesta, Yaya Toure, Abidal, Dani Alves, they quickly became some of my favorites as well.
It was something that was necessary in this world (because it happened). So, you can say something like my destiny.