The missing mother
The story focuses on a daughter's journey toward finding her mother. Eventually she manages the task, but when she gets there, they have business to attend to: Bee is trying to construct her adult opinions about life, and she has sought her mother for wisdom. Bernadette offers her a picture of freedom—not letting other people's assumptions hold her back. It seems that the "missing" mother has been within Bee's personality the whole time.
The missing letter
If Bee had behaved better at school, she would have discovered her mother's whereabouts very quickly. Ironically, Bernadette wrote her a letter, but not wanting Elgin to intercept it, she sent it to the school, but Bee isn't there anymore. If only she had seen it, the narrative could have been over just as suddenly as it began.
The new baby
Elgin impregnates his mistress, which is ironic by virtue of their relationship being an affair. Their family is predicated on Elgin abandoning another family, which may or may not bode well. Elgin seems happy, which is new, but in any case, the new baby puts a permanent damper on any hopes Bee might have had for seeing her parents reunited. Elgin has two families now. Bernadette will certainly not return to him now.
The irony of architecture
Bee seems to have her mother's tenacity and open-minded spirit, but the problem is that her mother is not some wild, crazy painter or something—she's an architect. That means she is both creative and extremely logical, disciplined, and mathematical. She also must work well with others, because she doesn't build homes from scratch. Bee ends up seeing that although her mother is adventurous, she is also an incredibly smart, hard-working woman who makes her own opportunities. The irony is that Bee realizes the importance of discipline where she thought she was going to find the importance of freedom.
The irony of mistreatment
Instead of treating Bernadette with honor for her unbelievable accomplishments in life, her family and friends basically treat her like a scapegoat for their frustrations. She unknowingly sells her prized architecture to the highest bidder—an angry neighbor who destroys the home immediately. Her husband leaves her for a secretary, probably because he likes the secretary's submissiveness. Her assistant is secretly trying to steal her wealth. Finally, the mistreatment is too much to swallow, and Bernadette returns to her life of being adventurous and awesome. It's ironic that she was treated with such petty hostility by everyone, even with her unbelievable success.
