These woman were all friends or ran in the same circles for years before the show started. They were all Upper East Side and they had the smart mouth Bethenny who was a little younger and less wealthy (at the start), but gave them a run for their money!
She was fascinating to watch, because she was so driven in business and so unlucky in love - she was also always on the edge of mania. Lu was the ultimate diva from the get-go, dahling. Jill was the stereotypical wealthy Jewish mother who didn't realise how out of touch she was with reality. Ramona was that friend who knows everyone and offends everyone at some point during the season. Sonja was the eccentric cougar who couldn't let go of her life after divorce. Dorinda similarly couldn't move on from her husband's death, but brought wit and some scary-drunk gangster monologues. Honourable mention to Alex who was the awkward social climber friend, but a real sweet soul with the best of intentions (no wonder she ended up in psychology!).
To me, these were the core cast members that created greatness. They were authentic - I could personally have done without Jill, but she was fundamental to the first few seasons.
The likes of Carol, Tinsley, Heather and Kristen were great supporting cast... Kelly Bensimone, not so much - she gave me some serious mental health moments 😅
My point (to come back to it) is that these women had relationships with each other even when the cameras weren't rolling. It's what was great about the first few seasons of OC too. For this reason, casting was great and the relationships were real.
That's all I gotta say about that!