Wal-Mart Bags

Would someone please tell me what it is with old people and Wal-Mart bags? Why the heck do they save them? I know a person who had over ten years of them socked away in 40-gallon trash bags in a storage shed. Is this the tendency of a generation that went through a Depression that feels like stockpiling these things represents a refusal to throw anything away ("we might use them someday"), or the sign of a psychosis deep, dark, and sinister?