Grocery shopping is something we all do, and it's highly personal. People have strong feelings about where and how they get their food. The proposed $25 billion merger of two of the nation's largest supermarket chains has the potential to affect how millions of customers buy their groceries. "State of the Cart" is a four-part series that examines different aspects of the proposed merger — its impact on consumers, on workers, on the communities themselves, and on our shopping habits.