For example, pictures look pretty cool when you capture a bride's engagement ring completely in focus and everything else is blurry and people immediately know the subject of the picture is the ring

Bokeh is dependent on the Aperture (shallow depth of field) and quality of the lens used while capturing the image. For example, take three shots of the same object such as a toy, kitchenware or garden tool (if possible, use a tripod). Set the first shot at F2.8, another at F4.0 and another at 5.6 and you will notice that in the first shot the background is blurred while the subject remains in focus

Both pictures (above and below) shot at F1.8

Of course, this effect can also be created in Photoshop. In that respect, I know two kinds of photographers: those who use Photoshop to enhance a picture and those who use to correct their short-comings. In any case, is always better to begin with the best possible picture we can create