>>149838717
Because unlike the main four, Sandy's not a miserable sadsack turbocuck or a psychotic bipolar asshole. Sure, she's the designated villain and thus got retconned into loving her job and cheating offscreen to make her less sympathetic, but at least she's not blatantly self-destructive. I find it easier to sympathize with a selfish character than one who's actions make no sense whatsoever.
And back in the before-times when the characters were still likable/nuanced and hadn't had all their positive qualities retconned or dropped, Sandy was the ubercat. She was more attractive and had a harder life than Lucy, more gentle/innocent than Daisy, more playful and fun than Paulo, and kinder/sweeter than Mike. So regardless of whether you judge the characters as they were, as they are, or as they could be, Sandy still comes out on top. The only way she doesn't is if you compare her as she is to Mike/Lucy/Paulo/Daisy as they could ideally be.