My friend Dina shared the news a few months ago that bobby pins are supposed to go in zig zag side down. It's true. I confirmed that fact for her at dinner prior to her blog post.
She, and Linsday, were stunned. And so is everyone else who I share this information with.
Lets cut to the chase: YES, put your bobby pins in zig zag side down (as in toward the scalp, or with the flat side being exposed). Why? Because it holds better and looks better.
The zig zag part of the pin "grabs" the hair beneath the section, and the smooth, straight part of the pin simply holds the hair down. Whether you are hiding your pins completely in a messy updo, or pinning your bangs back, always put them in zig zag side down.
Don't believe me? Give it a try and see how it works!