This panel lets you do some frivolous fine-tuning of your mouse, keyboard, and (for laptops) trackpad. It also unlocks Mac OS X's strange and remarkable Full Keyboard Access feature, which lets you control your Mac's menus, windows, dialog boxes, buttons, the Dock, and the toolbar—all from the keyboard (Reassigning all documents of one type). Here's a tour of the Keyboard & Mouse tabs.
The changes you make are tiny, but can have a cumulatively big impact on your daily typing routine.
Key Repeat Rate, Delay Until Repeat. You're probably too young to remember the antique once known as the typewriter. On some electric versions of this machine, you could hold down the letter X key to type a series of XXXXXXXs—ideal for crossing something out in a contract, for example.
On the Mac, every key behaves this way. Hold down any key long enough, and it starts spitting out repetitions, making it easy ...