A miniature, thought to be of Princess Charlotte. This style is also unusual because the bun is so large and high up on her head. The advantage of a higher bun from the portraitist's point of view is that it shows up from the front. Low buns above the nape of the neck are very elegant, but invisible from head-on. Think about the shape of your face when you decide where to put your hair and whether to do a central part or none at all.
Bangs soften the face, and they also emphasize the eyes.
This style tends to make long faces look very long indeed and short faces like mine look square. A fashion plate from 1811. This unusual plate lets you see both the front and back of the hairstyle. From the front the decoration looks like a U-shaped headband, but at the back you can see that it either goes all the way around or at least goes into the bun. I'm not sure whether it's relatively stiff, like plastic, or a beaded fabric band.