I don't agree that she "should" give you the egg either though. Again, your opinion is driven by emotion. You posted this as a warning to other sellers. A warning not to get emotionally invested in Kristy? A business transaction should have nothing to do with hurt feelings. You were under no obligation to give her breaks, and if those breaks came with conditions, you should have made those conditions clear at the time of making the deal.
Would it be a nice thing to do? Sure. But she doesn't have to, nor "should" she.