Daisy's reaction to a pile of shirts on Gatsby's bed is certainly odd, but in light of what she values in life, it makes some sense. Daisy's choices have always been about money, status and materialism. Daisy might have loved Gatsby back in their youth, but she is a lady of the upper class who couldn't have imagined actually marrying someone who didn't have the money or the status to support her lifestyle and her vision of herself. She marries Tom because he is the "right kind of person" for her to marry. He represents wealth and family name/status. So when Daisy sees the pile of expensive shirts, everything she had assumed about Gatsby in their youth is blown out of the water. He DOES obtain wealth; he DOES achieve all of the material goals that Daisy would have required. Daisy is upset to think that Gatsby, given enough time, could have been her true love and have fulfilled all of her girlish thoughts and dreams. Unfortunately, it is too late. She is married to Tom, and she knows, even if she doesn't acknowledge it, that she won't divorce Tom because that is not accepted in their social circles. She puts up with Tom's cheating for this reason. She will carry on an extra-marital affair with Gatsby for this reason. What she realizes though is that she is missing out on perfect happiness -- a man she truly loves and who loves her unconditionally who has the wealth that she requires. It is almost as if she is disappointed in herself for not trusting Gatsby way back in their youth because now she stuck in this less than satisfactory triangle. She could have "had it all," but she doesn't.