The QWERTY layout has a funny difference with for instance the french AZERTY layout. On an AZERTY keyboard, the parentheses () are directly accessible whereas the square brackets [] are not. On a QWERTY keyboard, this is the opposite : you need SHIFT for the parentheses () but not for the square brackets []. I've always wondered why the QWERTY layout favored the square brackets over the parentheses. Naively, parentheses are more common and should be more easily accessible...