@ScotchBunnet
The only clearcut case of a pro loathing their celeb, IMO, was Aliona with Gregg Wallace, and I couldn't blame her for that.
Remember (a hundred years ago) Brendan and Sarah Manners? I always got the impression that they properly hated each other and I’m sure he made her cry once.
In fact, I think he had a bad relationship with Lulu and Anastasia too...!
And Fiona Phillips. And Claire King.
Seemed to get on pretty well with Jo Wood, iirc. She's one of the few he did seem to genuinely 'click' with.
Karen Hardy and Gary Rhodes didn't get on well at all. And, of course, Lilia & Dominic Littlewood. Poor Lilia 
Oh, and didn't Steve Backshall make a formal complaint to the BBC about Ola? I think one of her former partners (Andrew Castle, maybe?) alluded to having had a similar experience too.
The 'ooooh, pretty sparkly, one big happy family' branding is extremely well maintained, but while they all insist that they've made a 'friend for life', it's just as fractious as any workplace: some great friendships, some polite toleration, some vicious personality clashes, and plenty of backstage hook-ups.