I would say that the northeast derby and rivalry is the worst.
I worked at tgi fridays at one low point of my life and had to train all the new staff that started.
The uniform used to be red and white strips but because of the hatred up there with the 2 teams they had to add black strips, it was one at the metro center and some other place i can't remember this was the only tgi fridays in the world with a different uniform.