In my usage, you can eat just a hamburger, but McDonalds won't sell you one; they'll insist on putting it between slices of bread, thus making a hamburger sandwich of it. If you want to eat just the hamburger, you'll have to peel off the bread and throw it away. They also sell fried-fish sandwiches and, in an absurd attempt to seem "healthy", chicken sandwiches.

Around here Starbucks serves mostly desserts, but that might be a regional thing.