The most obvious battleground is the bread. A sandwich typically embraces soft, sliced bread, a crusty roll, or a baguette—versatile and neutral. A hamburger, however, demands a soft, round bun, often lightly toasted and slightly sweet.
This isn’t just about shape; it’s about structure. The bun is designed to hold a specific filling—the patty—without disintegrating. It’s a vessel built for a single, glorious mission. A sandwich’s bread is often a supporting actor; a burger’s bun is a co-star.