2. You-see-what-you-wish-to-see factor: The hag was disgusted at seeing what she saw, and walked out cursing the womb that gave the young man his life; in contrast, the young beauty was astonished at her new discovery, her medical school-trained professional curiosity took over immediately, and wasted no time switching on an extra light to take a closer look at the hitherto-unheard-of medical phenomenon.
3. Eyesight factor: One's eyesight generally deteriorates as one ages.
4. Beauty/excitability factor: No explanation necessary.