How many times you typed long text in MSWord and after you noticed "Caps Lock" were turned on? All you typed were case letters and you have to type again. You can change case with Shift + F3, too, but you have to make further effort and you will get nervous, that's almost shore.

Here's a tip how you can avoid that. You can attach sound to Caps Lock key and you'll here it when you turn it on by an mistake. Here's how you can do that trick:
Go to Start - Settings - Control Panel. Now go to Accessibility Options. Menu "Accessibility Properties" will open. There, chose "Use Toggle Keys" in "Toggle Keys" .....in lower meny, click OK