The Phil vs Kai has been the best rivalry in bbing for the longest time. And Phil is at his best when Kai competes, because he knows if he slips up, Kai when beat him. And Kai has beaten him several times.
I would not agree for 1 reason only: It wasn't a real rilvary, like Flex vs. Ronnie or Jay vs. Ronnie. In those cases the tension between was insane, do you remember when Flex turned his back on the crowd & the judges and gave them the middle fingers in 1998? What about when Jay took the Arnold off in 2005 just to focus on the Olympia and take Ronnie down once and for all? What has Kai done, really, in this "feud"? For one thing, despite having a better back and legs, he's not as good as Phil overall and never had a chance to win. If it was a real rivalry they'd be neck to neck, which they've never been. And then his sordid past obviously keeps him from being first even if Phil retires. Finally his blubber fest last year when he didn't attend...really took the wind out of his sails as a credible opponent.
It sucks because the sport has never had as arrogant and self-centered a champ as Phil, other than Dexter (for 1 year). And Dexter's not really arrogant, he's just a prick, like that time he won the Arnold and was basically a dick to Arnie when answering his questions with short 1-word "you're dumb for asking me this" answers.
