Collars really make an impact on your entire look. The demure "peter pan" collar coveys an innocence that can belie the true nature of the person underneath. A dainty lace collar will make you think of a few decades back and imagine that you smell dusting powder and not even think of saying the word damn in front of that person. The exagerated pointed or rounded collar immediately takes you to the 60's and 70's reminding you of London or Funk. I often see coats with the shawl collar and fur surrounding the shoulders and right away think of a lovely grandmother lady or a cool hipster over in Williamsburg shopping at vintage clothing stores and making the most of a decade gone by.
In Roman Holiday, the fun black and white movie from 1953, Audrey Hepburn wears a little white blouse with a small collar throughout most of the film. The brilliant Edith Head designed the blouse to be worn in a variety of ways; open collar, buttoned up, open collar with a small silk scarf tied around Audrey's neck, buttoned up with the scarf tied on top with the collar up; such a simple variation but to marvelous effect.