My first encounter with Pokemon wasn't through the games or through the show proper. It was actually at the Bellevue library. There were some books that turned out to just be episodes of the Pokemon anime but novelized. The one I picked up was about Ash, Brock, and Misty running into Sabrina, and her using her psychic powers to turn the companions into her dolls. Ash got the hell out of there, but came back after making friends with a Haunter and eventually getting her to laugh.
Sabrina made a strong impression on me. I came to like Haunter, too, though I ended up liking Gengar the most despite Haunter being the more important mon in the story. Learning that she was actually a lot less spooky in the games was weird. And then learning she was a lot worse in the manga was something else. And then there was Electric Tale of Pikachu, which had both her and Haunter again but in very much switched hero and villain roles.
Well, the long story short is that she was part of my very first impression on the franchise. She kind of has a special place for me because of that.