Although crocheted using a hdc, the texture is created by inserting the hook under the back loop and the rear horizontal bar, resulting in the front loop as a bar running the width of the fabric that faces me when working (see the underside of this hat pictured below). This side is the wrong side and will remain hidden. The reverse side, or the side facing away from you, creates a cool texture like a sideways garter stitch. It should be noted that the wrong side can actually be the right side when worked in sc for a hat, which creates an interesting texture as well.

Some yarns, like bamboo blends, tend to produce a heavy fabric. When using a heavy yarn like Patons Silk Bamboo, you may want to substitute a slightly smaller hook so that the weight of the yarn does not stretch the hat. This is particularly true if you tend to crochet loosely.