I will be honest and admit that Jackie's personality reminds me of my mother in many ways. She appears to be someone whose self concept is very dependent on being someone others admire as a highly moral and upright citizen. The upside of this is that it can prompt good decisions, gracious actions and generosity. The dark side is that it can cause one to shut down any observation that one's motivations are anything but good.
When another person verbalizes an offence, the first reaction will be defense of the intent behind the offending action. This generally makes the other person accept the non-apology and move on. If you press further, there is reiteration of angelic intent, assertion that you know the kind of wonderful person they are and how they would never hurt you on purpose. Then, if you push again for the actual apology, there will be anger (illustrated by Jackie) or tears and martyrdom to the point your instinct is to retreat or wish you never started the conversation and sometimes even doubt your own memory/sanity. Friends and family members generally talk about this person behind their back and roll their eyes but, confrontations are rare and thus, this type of person can remain protected from criticism and self assured of their own righteousness in most situations.
I have learned to choose my battles carefully, preplan my points, and gird my loins when I do choose confrontation. I also know going in that my goal is to stretch my own growth in the area of standing up for myself (because I couldn't as a child), possibly protect my child from emotional harm (if applicable) and an apology from her is a possible bonus. I suspect people like Jackie actually knowing they are wrong makes the reaction worse especially if they become aware of it during the course of the conversation.
All things considered, Buffy did great. Mr. red12 commented on how supportive her husband appeared.
I also noticed how Heavenly shut her mouth when Buffy took it to her. Further proof of what a bully she is. I do think Heavenly's defeat there heightened her retaliation against Scott and poor mood concerning her husband enjoying himself.