Because she grows on you, and is a tough female character that's a love interest with the main lead. I know, I know. The "tough female lead" card can be played a bit awkwardly (Merida) and is something tryhards who bash the classic say they love but I mean it without being ignorant. Astrid had to grow up being strong, people had expectations for her and she wasn't just a shoe-in love interest that happened to be badass for the plot. It made sense why she was the character we saw grow, and we ended up rooting for her in the process without DreamWorks using #GirlPower as a plot device. So yeah, I like her. Duh, that was easy.

Simply adore her <333 Definitely one of my favorite animated characters! We pretty much grown up with her during the movies and TV series. She has a lot of different sides and traits.
A complex character, never boring or too perfect. She has flaws and that makes her real and relatable.

She just felt very stereotypical to me in the first movie. I liked her a little better in the second movie though.

standard-isssue "strong female character" which is a trope that bugs the hell out of me personally.

^ Same

She's sincere and determined ☺

pretty neutral about her

She gets really excellent character portrayal and development in the TV series. Just based off the first movie, though, I'd be neutral.