They find it almost intolerable having to coexist in the same city.
But yesterday Scottish football’s bad neighbours just about managed to take what they needed from their final skirmish of the season in a blockbuster of a match which just might end up as a microcosm of an entire season.
Celtic escaped with the point which means the title is now secured barring an unforeseen act of God. And Rangers got out of the east end with pride intact and without incurring further casualties ahead of a campaign defining Europa League semi final second leg against RB Leipzig.
It was an Old Firm ruckus which began and ended with generous cuddles between Ange Postecoglou and Giovanni van Bronckhorst and we could be about to witness the most unusual of circumstances where both of these managers go into the summer with their credentials completely copper bottomed and being love bombed by their own supporters.
Two trophies in one season for Postecoglou will represent a stunning return for a man who arrived here less than a year ago, apparently on the ultimate hiding to nothing.
That the title is now just one more win away against all the pre-season odds means the big Aussie’s hero status is already secured among Celtic’s adoring supporters.
But Van Bronckhorst might end up trumping the lot should he go on form here to lead Rangers to a European final and then book-end the season by lifting the Scottish Cup at Hampden on May 21, three days later.
Both men should savour such a happy ending because it will almost certainly never happen again. In 12 months from now it’s inevitable that one of them will end up running out of goodwill because that’s just an unavoidable fact of life in this particularly unforgiving part of the world.
Never again will they both be able to saunter off into the sunset, surrounded by all this warm fuzziness and, as a matter of fact, they deserve every bit of credit which will come their way over the final weeks of a once in a generation campaign.
Let’s not forget, it was only a couple of weeks ago that Van Bronckhorst found himself at a bit of a crossroads where his standing with his club’s supporters was concerned.
But by beating Braga to reach the last four of a European competition and then knocking Celtic out of the Scottish Cup, the Dutchman came through a critical moment.
And the performance his side put on at Parkhead yesterday will only have added to the feelgood factor where Van Bronckhorst is concerned as, once again, his game plan was very close to being faultless even though he is currently operating without a recognised central striker and one hand tied behind his back.
That Rangers were the better team is not really in any dispute. Celtic managed just one shot on target over the course of a breathless 90 minutes and even though Jota made it count, volleying home from close range after Borna Barisic had slept walked into a recurring derby day nightmare, even that moment came against the run of play.
Rangers had started the game looking brighter and playing with far greater purpose than the champions in waiting and ought to have hit the front early on when Ryan Kent missed a carbon copy of the chance which Jota gobbled up at the other end.
And even though Celtic seemed to be settling into their creative rhythm towards the end of the first half it was Rangers who grabbed the contest by the scruff of the neck again immediately after the interval.
They did not let go until the last kick of the ball and will have returned across the Clyde yesterday afternoon feeling shortchanged by just a single point.
Certainly, when Fashion Sakala fired them level in 67 minutes it was no more than they deserved and the Zambian could have won it before the end when he smashed a shot off the base of Joe Hart’s left hand post.
But the truth of the matter is it wouldn’t have made any meaningful difference to a title fight which had already been won and lost before a ball was kicked yesterday afternoon.
Celtic’s almost immaculate consistency over the second part of Postecoglou’s first season in charge has seen to that.
Van Bronckhorst, on the other hand, found his side stuttering at crucial moments which is precisely why he was feeling the heat at the start of last month.
That’s no longer the case now, though, as he prepares for 90 minutes - or perhaps it could be 120 - which stand between Rangers and a place in history.
Even if they should fall short and fail to find a way past an excellent Leipzig side on Thursday night, the monumental efforts of Van Bronckhorst and his players will not be lost on the Ibrox regulars.
This marathon run against all the odds has already surpassed their wildest dreams and yet it does feel as if the story might have some mileage still to come.
If Rangers do overcome the Germans to make it all the way to Seville then Van Bronckhorst will take on legendary status even despite allowing the domestic title to slip through his grasp. And what if he should actually win the thing?
They’ll be asking him where he wants his statue, never mind conducting a post mortem on the one that got away.
Yes, these really are the most extraordinary of times. A summer of love in Glasgow? Rest assured, it will never last.
