Eating and home life go hand in hand. In many homes, the kitchen is the center of family life, and barbeques and potlucks are popular ways to gather a crowd. So, just by finding out that eating is involved in this poem, we are placed in a home setting.
the plums that were in the icebox (2-4)
Ladies and gentlemen, it's time for some time travel. We've got to jump back to another time in American history—when either the family still had an old-fashioned icebox, or when fridges were still called iceboxes. It's not just appliances that have changed in American homes since the 1930s, though, it's the families that live in the homes, too. Our women are more likely to work, parents are more likely to be divorced, and television, not around back then, plays a large role in our lives. But to be honest, we're still stealing each other's plums. Or is that just Shmoop?
you were probably saving for breakfast (6-8)
Now we get a taste of the family dynamics. If a note is necessary to let someone know that their intended breakfast has already been eaten, we know these folks don't exactly gather around the table for three meals a day. But they're still connected. After all, it's the little things, like notes on the refrigerator, that make a home a home, and not just a place where you live.
Forgive me (9)
Well we know now that the members of this household ask for forgiveness, and communicate. That's a good sign. Even though the speaker has wronged someone he lives with, by eating their plums, he's nice enough to leave a sweet, sheepish note. He could have left one that said something like, "Ha ha, no plums for you, sucker!" Instead, he shows obvious consideration and care. It not only excuses the speaker from eating the plums, but also shows that he's thinking about the person to whom he's writing, even though she's not awake right now.