Chicago Fans teach this annoying chant to their children when they are young.
I was at a game in Chicago against Detroit last year and observed this phenom unfold in front of me...
A lady walks down the stairs behind me with her daughter and when she reached the bottom of the stairs to turn and walk down the tunnel toward the concession area, she picked up her daughter, smiled, and said, "Can you say Detroit Sucks? Can you say Detroit sucks?" and walked away into the Chicago Oblivion...