Honestly this last little while BAP hasn't exactly been good enough to have real rivals, but back when I was GM of Vancouver in the S30s they had a real strong rivalry with Kelowna. For as long as I've been in the league I don't think there's been as strong of a rivalry as this one. Both teams really hated each other and we had some very tightly contested playoff series against them including a reverse sweep against us. From my understanding, this rivalry had been going on for quite a while, even before I had shown up in Vancouver in S29. It also doesn't help that the two teams are geographical neighbors, but I honestly think that was mostly coincidental when it came to the rivalry. These 2 teams disliked each other enough that even had they been in different conferences or on opposite ends of the country they still would have been rivals.