From memory, I believe Mo was diagnosed with Bipolar, so she has her high and low moments.
As for Pim, never warmed up to her. From memory as well, wasn't she frozen by Ch. 7 for throwing a fit and pulling out of a lakorn for playing a supporting role when she thought she was popular and good enough to be a lead? Her fans, too. In their eyes, she can do no wrong.
If this is Pim's second time meddling with a taken man, or perhaps even more, the girl has major issues. It's not even coincidental anymore that she happens to fall for taken guys. It's deliberate, which isn't a surprise. For females who take other females' men, they want to prove something, they act like they're all that, that they can have anyone they want, and to take a man who already has someone, it's a victory, a tally mark, some kind of high. That matches with the rumors of her being a brat behind the scenes, thinking she's better than others.
As for Matt, sorry, never warmed up to her either. She has always had rumors of being a hard to work with type personality and this interview just proved it. Matt isn't wrong in trying to protect herself from unnecessary drama and rumors with this guy, but she could have handled it better. She was rude, not blunt.
As for Sean, I'm starting to see why Esther distanced herself from him. He's no better than Pim if he cheated. Poor Gyp. She's always so honest with everyone and they screw her over.