Life/death experience
YOUR CLUB, supposedly, is for life. When they created that marketing slogan for the club championship, one life, one club, they rarely coined a truer statement.
You develop fondness for your club because of your father or an older sibling or a player you enjoy watching, but this fondness is developed early in life and should never leave you. You stick with the hand you were dealt in early childhood, a hand that will affect moods and the way the rest of your life is lived.