Everybody has their own type of hair texture. Either it be "Nappy" also called coarse,straight,curly/naturally wavy. Any hair texture can get hair.
White people can even get waves. BUT as I have said before a wave is nothing more than a straightened curl. For white people's hair texture, it is naturally straight. But usually when it reaches a certain length it starts to curl. So you must WOLF until it starts curling and then you must brush and brush to straighten out those curls.
But anyways your hair texture determines what type of waves you get. For example, Nappy/Coarse hair gets you Micro Waves(Skinnier Waves) and the naturally curly(Cuban/Jamaican hair) will get the deeper waves. So if you wish to get those amazing deep waves and you have nappy hair you will have to settle with what you got which are micros. Not everyone's waves will come out the same, it all depends on your hair texture.