Lindo Jong tricking her superstitious mother-in-law into believing that her arranged marriage with her son was angering their ancestors, thus allowing her to leave it without dishonoring the promise she made to her parents.
She also improved a pregnant servant woman's life who now had honor for her child AND a serious jump up in status.
An-Mei's mother timing her suicide to fall two days before Chinese New Years', knowing that Wu Tsing would not want to deal with her vengeful spirit (folklore states that a dead person's spirit returns the third day after he or she dies to settle scores), especially not on such a holy day, and would treat her children well.
Can we just acknowledge that this is the kind of book where someone COMMITTING SUICIDE is a crowning moment of awesome?
In the film adaptation, An-Mei declares that now she has power over the household. At the funeral, she grabs the hand of her younger (half)brother, whom Second Wife stole away from An-Mei's mother, and shouts at Wu Tsing and Second Wife—who looks absolutely terrified of An-Mei and probably even more so of her mother's ghost, knowing that she'll be facing retribution for her poor treatment of her.
The ending of the Magpipes story. An-Mei is told a tale about a turtle who must swallows its tears because the magpipes simply will feed on the tears and laugh at its misery. However, in the wake of An-Mei's mother suicide, An-Mei thinks of the ending where the grief of the impoverish and unfortunate becomes so great that they defeat the Magpipes.
Rose standing her ground against her emotionally abusive ex-to-be, affirming that he cannot just cast her aside and just take his possessions just to settle in with his new bride.