Say you are talking to someone, your computer goes to sleep while you are not on the computer. You hate that you have to log in again. It happens many times of the day. You may not want to change the sleep settings (or locked out evil IT department Group Policy Objects).
Here is a little tip to cheat the system. Click the clock on the task bar to bring the analog clock and calendar like below. Leave the mouse on top of the analog clock. Your screen won’t lock or go to sleep. The Analog clock second hand movement is tracked by your mouse, so the computer thinks you are busy doing something.