Makes total sense when you remember C's assembly roots. On most architectures including the PDP-11, the program counter just moves to the next instruction. To make it do anything different, you need a jump instruction, and that's what the "break" means.

To a sibling comment: C# does permit fallthrough, just with ugly syntax. You can "goto case 2". http://stackoverflow.com/questions/174155/switch-statement-f...