Sarah, the Invisible Matriarch

First, Avraham (Abraham) passes Sarah off as his sister--twice!

Then, Sarah gives her maidservant to Abraham as a surrogate mother because G?d doesn't bother telling her that she's going to have a child of her own, eventually.

Then, when G?d finally reveals--to Avraham!--that Sarah's going to have a baby at the age of 90-something, G?d yells at Sarah for thinking skeptical thoughts.  Why would G?d expect Sarah not to be skeptical?  And why is it that the only time that G?d speaks directly to Sarah is to rebuke her for doubting G?d's power?

Then, G?d orders Avraham to sacrifice Yitzchak, who's Sarah's only child, and neither of them bothers to tell her.

No wonder Sarah died.  What's the point in living when the only reason you exist is to prove that G?d has complete control over birth and death, and no one--human or divine--actually seems to care whether you're alive or dead?

In Sefer HaMinhagot (The Book of Customs) 18b, R. Asher of Lunel, much to his credit, wrote a midrash (an interpretative story) that connects Sarah's cries, when she learned of the near-sacrifice of Yitzchak, to the tekiah notes blown on the shofar.  But in the actual text of the Akeidah (Binding of Isaac/Yitzchak) in the Torah (Bible) itself, Sarah is completely absent.