It might seem like a pretty straightforward issue, but using bobby pins is more complicated than you think. There are two sides for a reason. One is ridgy, and one is smooth. To get the best grip possible, the wavy side belongs against your head. This will give you a better grip, especially if you have silky smooth straight hair. That's always a challenge when it comes grip, we know.
If you ignore our advice, all hell won't break loose. But your hairstyle might! Try it out, and see if the pin placement makes a difference. Some gals say it's a game changer!