It can be sad and sexy at the same time. The tension can be part of the appeal.
It can be like a striptease: seeing her with long hair and anticipating what she will look like with short hair. When she first sees or plays with her new short hair, the combination of being nervous, excited, and newly confident at the same time can create a sexy vibe.
Long-to-short hair is linked culturally to coming-of-age as a mature sophisticated woman.
If you like seeing brushing, braiding, buns, and bun drops, a haircut is just another progression of styling which emphasizes how delicate and fleeting long hair is.
If you like long hair for the sake of long hair, the longest her hair will ever be is in the photo taken the moment before it is cut. There are fantastic long-hair photos on the hair selling websites.