Lion, Apple's newest Operating System with over 250 new features is going to have the famous autocorrect feature that was there in all Devices running iOS. The auto correct feature on iOS was a source of major controversy. Some liked it. Some didn't...
In iOS if you wanted to accept the suggestion you pressed the spacebar. if you didnt, you tapped the word. Now that much more simple on a device where your fingers are already located close to the screen. In Lion, if you want to accept the change, you press return ( simple enough ) but if you don't want to accept the change you have to stop typing, move your hand all the way over to the mouse and click on the 'X'. Personally this seems like way too much touble just too type the spelling you want. In my opinion, in iOS its great, in Lion, not so much. However, I believe that there will be a way to disable it in Lion.