I was a child in the 80's with curly white hair, I hated it, everyone else loved it. I was singled out because of it and always told it was special, enviable, etc. I never liked it myself and thought people were mad!
Hair stylists encouraged me never to colour or straighten it as people would pay a fortune for what I had naturally.
This lasted up until my mid twenties, so into the 2000's. And then suddenly the compliments vanished and people even occasionally told me they had sympathy for me having to suffer curly hair! 
Hair stylists in the past 10 years have even said my hair is 'problem' hair.
Such a turnaround!
This went hand in hand with straighteners and ghd's exploding on the market.
So I guess I lived through a fashion change, a massive alteration to the perception of curly hair. I have always semi straightened mine and never liked the curls from being a little kid, so none of the fads really affected how I wore it, but I did notice how deeply and suddenly the rejection of curls came about.
So, all the way to the present day, I still see people trying to avoid wearing their curls. It is often seen as 'unprofessional' or untidy, and people say they don't feel groomed or well put together with their curls.
Strangely, nobody said that back in the 80's or 90's.
do you believe fashion dictates this, and our perceptions of what is well groomed?
Will curls have their day again, and flat straight hair become the 'ungroomed' look?
Having lived through these changes of perception and noticed how others react to my hair, it is quite interesting.
I take the middle ground, I prefer it wavy, haha!