Jamie Lannister is the textbook example of this and no I don't count the final season
1
Steve Harrington- Stranger things
2
Ba'al in Stargate. Hated him. Now one of my favorite baddies in all of science fiction.
3
Pennsatucky (Tiffany Doggett) from Orange is the New Black. She gradually gets less and less sh*tty over the course of the show.
4
I disliked Tom when I was a kid because he always tried to eat Jerry, but eventually I finally understand that it's just a cat who is doing his job and that Jerry is kinda an @ss.
5
Madame Avasarala, from The Expanse. At first she's just shown to be like any other cut throat politician, but as the show goes on and on, it becomes increasingly clear that she is one of the few people with power who don't just see it as that: power. She actually tries to make the solar system a better place(or at least stops it from blowing itself up), and while her methods are definitely unorthodox and sometimes morally wrong on their own, in the end she does just that.
6
Finnick from The Hunger Games series
7
Ahsoka Tano. Started with "Skyguy" and "Artooy" (which is stupid that she's extending the shortened version of a name) and I just wanted her gone. By the end of The Clone Wars, she's badass as hell. That's good character development.
8
Klaus from Umbrella Academy
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Charles from M*A*S*H
Growing up is really interesting in regards to TV shows and movies and stuff.
You die liking Jerry or grow up to feel sorry for Tom
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Nebula
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Professor McGonagall.
Loved her even more with Maggie Smith playing her in the movies
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Zuko from avatar the last air bender. Throughout the series he just got better and better. He’s the definition of character development.
13
Regina Mills “The Evil Queen” Once Upon a Time
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Sawyer from Lost
15
Donna Noble - Doctor Who 2006-2020
When she appeared in The Runaway Bride I was so glad she was gonna be a one off... then it was announced that she'd be a reoccurring character and I was all "oh damn"... by the end she's one of my favorite companions and I still can't watch her last few episodes without tearing up or even out right bawling.