Renaming files and folders in the Finder is a pain. You have to click on the thing to be renamed, wait several seconds and then click again to get the editing box. Worse yet, often you have to go through several wait/click cycles before it actually works. There is a much quicker way to do this. Click on the file or folder to be renamed, then hit the Enter key on the keyboard. You'll instantly get the editing box, no waiting or retries required.