Niners-Seahawks rivalry: We hate each other because we're so alike
The uncivil war begins with the coaches. San Francisco's Jim Harbaugh and Seattle's Pete Carroll launched their hate affair as North-South competitors -- at Stanford and USC -- and things got more malevolent after they both landed in the NFC West.
"Seahawk fans absolutely haaaate Harbaugh," said Holifield, a high-tech attorney who will fly up to Seattle on Sunday to join his 'Hawk-loving family at CenturyLink Field. "They haaaate watching Harbaugh on the sideline, scowling, gesticulating and bitching."
While Holifield's wife, Michele, a bleeding-heart Niners fan, will barely tolerate watching the game with her turncoat husband, she reports that "people down here haaaate Pete Carroll, smiling, chomping on that wad of gum, running up and down the sideline."
The article goes on and on but I reached my saturation point and had to both bail... 
and barf--
All I can add is I hated the Niners way before Jim Harbaugh was born in the days before Gay rhymed with San Fran... 
and John Brodie was one of the leading celebrity endorsers of the Church of Scientology.
As to Pete Carroll was on my hate list back in the 90... 
when he coached the Pats and Jets with the same arrogance he does today.