Una, I can name a few changes.
Most people felt like their style changed when they went short; I felt like mine changed when I grew my hair out. In late high school/early college, my hair was highlighted quite blonde and was about shoulderblade length at its longest; in late college, I let my hair grow about this long again. I felt quite feminine, but in a way I also felt boring. (As I mentioned to Kate in my comment above, my hair is TOTALLY flat when it's long, unless I have an exceptionally good cut; and even then, it's a challenge to get it to look good.) I felt like the only style that worked on me was to have my hair blow-dried and flat-iron or curl the ends. I don't look good in a ponytail or half-ponytail or most updos - my hair doesn't have a lot of body when it's pulled back and it's unflattering. So I really struggled to try to wear brighter colors or accessories to make up for feeling like my hair wasn't quite so fab.
In between the two "long" phases, I cut my hair short and started dying it red. Short hair has always made me feel fresh and cute and more willing to try styles that were fun and new; red hair made me feel sassy and a bit daring, less "sweet" than the long blonde locks I'd sported in the past.
In my most recent cut, while I'm nowhere near a pixie, my asymmetrical bob is on the very short end of the bob spectrum, and it is incredibly layered and razor-cut, and I can play with product to add a LOT of volume. I feel like this is the bit of edge that I've needed to temper my pencil skirt/dress wardrobe.
I know this is terribly un-specific, so it may not be too helpful, but it's been fun to walk down memory lane and read the other posts. Thanks for starting this thread, Una.