Someone new to Photoshop might be tempted to dismiss Gaussian Blur as something that makes stuff blurry. But the stalwart Gaussian Blur goes to the heart of what makes Photoshop Photoshop.
The term Gaussian might be best described as the thing that makes another thing drift eventually and incrementally into oblivion. Gaussian Blur underlies the Feather command, the Drop Shadow layer effect, and even Unsharp Mask. Simply put, it is the heart of detail-, depth-, and focus-enhancement in Photoshop.
To learn how, when, and where to use it, click the image below to launch the video in another window.