For many Harry Potter fans, there was a fairly significant difference between how they imagined Hermione Granger in the books and how she appeared in the movies.
We decided to create photoshopped depictions of what she may have looked like if the movies followed the book descriptions more closely. What we found may surprise you.
Harry Potter and the Goblet of Fire: A momentary change in appearance.

Conclusion:

While some might debate casting someone as beautiful as Emma Watson for the role of Hermione (and then not changing her hair and teeth), with more research it is clear that Hermione is continually described based on her intelligence and personality and not her appearance. With no definitive look described by J.K. Rowling, Emma Watson may have been the perfect fit...even if they ironed her hair smooth.