My Mom and sister have straight hair, and go to the beauty parlor frequently to get it wavy. Then it's the curling iron every morning. I still remember their home-perm days, and some of the mishaps that resulted. They'd kill for wavy hair.
My wife has naturally wavy hair. She'd give anything for it to be straight. She wants to grow it longer, but when she does, it just gets wavier and curlier, and you can't tell it's any longer except when it's wet.
I told my wife she should try the relaxers that black girls use. I assume those would work on her, although her hair is wavy and not tight tight curls like black people have (we used to call it kinky, but now I'm not certain if that's a racist term... if it is, it's not intended to be).