In a single narrative, it’s satisfying to an audience if the character changes. It doesn’t matter whether the character is a better or worse person, what’s important is that they’re not emotionally static. So the obstacles that you throw at the character, and that they overcome on the route to achieving their tangible goal, changes them.
Often, when a writer has grasped the idea that the character has to change, with so much else to think about, they chuck the emotional shift in at the end. So for example, a character is anxious all the way through and right at the end, the sun comes out, harps play and, hurrah, he finds his inner calm. This feels clunky, and exactly what it is, shoe-horned in.
The way to avoid this is fabulously simple.
Say you have decided that your protagonist is a cold-hearted corporate monster, but by the end of the narrative he or she becomes a self-sacrificing philanthropist.
1 Make a list of the emotional stages between being a cold-hearted corporate monster and a generous, kind person. These need to be roughly 8-12 stages. So for example, greedy, in denial, defensive, obsessive, envious, insecure, ashamed, hopeful, determined, proud, tranquil.
Do not obsess about this too much.
You now know, for example, that in the first act you will show your protagonist as greedy, in denial, and defensive. This should suggest scenes that will SHOW the individual emotional states and the audience will have a sense that the character is gradually changing.
This may sound prescriptive, but I promise you, no one will see the joins.
And if this isn’t clear, please drop me a line and I will clarify.