* She's not your typical princess: Fiona is strong, independent, and doesn't fit the traditional damsel-in-distress mold. She's capable of fighting for herself, even if she initially needs rescuing from the dragon.
* She's a good person: Fiona is kind, compassionate, and cares deeply for others, even after being imprisoned for years. This makes her a sympathetic character that people would want to see happy.
* She's genuinely in love with Shrek: This is the most important factor. Despite initial reservations, Fiona falls deeply in love with Shrek for who he is, not for his outward appearance. This unconventional romance makes their relationship relatable and something people want to see succeed.
* She's breaking the mold: By choosing Shrek, Fiona rejects the expectations placed upon her as a princess. This is a powerful message of individuality and rejecting societal norms, which many people can identify with.
Ultimately, Fiona's "rescue" isn't just about her being a princess. It's about the connection she forms with Shrek and the shared journey they embark on. It's about two flawed but lovable characters finding happiness in each other despite societal pressures.
It's important to remember that the film uses the "damsel in distress" trope ironically. The entire movie plays with expectations and subverts them. Shrek is the hero, but Fiona is the one who ultimately chooses her own destiny.