So Sai is a little immature, childish, stubborn but shes always consistent in her behavior and Kind hearted. So whether its pp, trimurti or anyone else she doesn't have malice in her heart for anyone. Her intention behind calling pp was purely to make sure she doesn't feel left out. It was a "family" gathering. She was genuinely concerned about her headache and in todays epi she didnt initially read pp's anger as jealousy right away - usually she would have but today she genuinely thought the anger n irritation was because of headache maybe even "hanger" if she had been in the room all day. The conversation was unecessarily dragged but thats just itv side effects. They have to stretch things for drama. Discussing the party, virat etc was not needed but pp brought it up. Sai only replied. Perhaps Sai should have backed off but she was just being her usual self. I think with time that childish zidd will get better. Also I think Sai will soon see maybe in the next epi itself that pp doesn't have a headache . Her reason to stay away is jealousy that Sai's birthday is being celebrated by Virat in such a grand way. Thats the point of the long conversation i guess- for Sai to see that pp's issue is that Virat is celebrating Sai's birthday. If this was virat celebrating mohit/karishma/devi's birthday there'd be no issue. The woman is so petty that she is upset that a girl who is an orphan is getting to celebrate her birthday. She has no insaaniyat. If she did she would have ignored her "jealousy and pain" to just fulfil her family obligation of being present. Even trimurti gave attendance in this party despite not liking Sai.
Also unlike Sai, Trimurti n PP can be ziddi too but only with Sai and only for bad things. They give each other leeway and want to be forced for anything but don't accord the same courtesy to Sai. They forced her to apply alta, grind mirchi, Attend pp parents anniversary etc against Sai's wishes but unlike Sai their intentions were also malicious right from get go. Pp's motive behind calling her to the anniversary was only to insult.
Log aksar galti karte hai but intentions are very important. Sai's intentions are pure so its always possible to look past her flaws just like Virats. Thats why we as audience root for them.
Pp has been shown lacking insaaniyat also. The point is not that Sai irritated her to the point of unintentionally pushing her. The point is her reaction afterwards. For a millisec she looks shocked that Sai fell but instead of reflexively going to help, she is more worried about Virats reaction, starts defending herself. It shouldn't have mattered that Virat came to care for Sai. If I uninentionally pushed someone my reflex no matter how many people were around to help would be to hover around the person apologizing and trying to help them. But pp lacks basic courtesy. Sai would never behave like that. She prevented pp from tripping during Ladakh trip scene. She asked pp to stop grinding chillies as soon as she saw that pp was getting hurt too. She cares about pp eating, her health- because puts insaaniyat first despite disliking her as a person. She truly shows her maturity because despite all personal issues with pp, Sai sets it aside to fulfil certain obligations and never in her dislike does she blur the boundaries of right/wrong in her head- she doesn't want to see pp hurt or in pain just coz she doesn't like her. Whereas pp does.
Her concern is not that Sai is hurt but how Virat will perceive her after the incident. Even in her irritation, pp could've said- sorry Sai, galti seh haath lag gaya, and offered her a hanky to stop bleeding or a bandaid. But she stood there accusing Sai of annoying her rather than postponing her rant to attend to the injured person. It shows her character.
So pp absolutely deserves a solid thrashing from Virat n rest of family too. Maybe shivani can give her a good dose . And pp needs to apologize to Sai no matter how irritated she is with Sai because injuring someone even unintentionally is not ok.