Vim. Moving around
Vim is not a mouse driven program. With other editors, you use the mouse to place the cursor at the desired position. This seems to be fine. However, you do not realize how faster you can move using a command approach as in Vim.
In Vim, you move around the text using different commands, that is, keystrokes while you are in command mode. At the beginning this may result confusing or even seem a waste of time. However, once you get used to it, you will never leave it and you find it to be faster than any other method.