I just read the part about S5, and you're right, I hadn't seen it that way. I definitely thought it was preposterous to have a 20-year-old as the guardian to a 14-year-old. (Yes, there are twenty-year-old mothers, but not to kids that old. Also, those are their own kids, who may have been conceived and carried consensually, not their siblings.) Plus the kids on "Party of Five" went up to what, 25, 30? Old enough that the eldest had a real job, anyway.

I think Buffy took a lot of crap because of how responsible Joyce came to see her as. (And maybe the "love her as I love her" was partly monk-influenced?) On the other hand, with the hospital incident, it's clear that Joyce was not compos mentis, so in that particular instance I let her off the hook. She has a tumor pressing on her brain and is having breaks with reality (Buffy, fat?!), so it's not too surprising that her judgment was off.

Besides, Buffy could have soothed her and said it was better to keep her in the hospital, but Buffy was (and became more and more) a pleaser, someone who thinks they have to be perfect and do what others want in order to be worthy of love and friendship. And she's the Slayer, so she thinks of herself as omni-competent, or needing to be omni-competent.