I don't have to worry about straightening my hair. It is as straight as a ruler without a perm. I have a big cowlick in the back of my head, right near the crown. It doesn't show when I have curls.
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Do not ask the Lord to guide your footsteps.
if you are not willing to move your feet.
My hair is as straight as can be, always has been but a straightening iron smoothes down those flyaway hairs that always pop up, so it's not just for taking away curls but kinda keeping your 'do' together, smooth. That is why I have and use mine.