Like many things in the writing world, there are expectations for everything. Plot, characters, subplots, romances, antagonists, protagonists, settings, writing style/narration, etc. Also within the writing world are numerous helpful hints, charts, blogs, and classes dedicating to making each of these things better. Fuller. Expanded and enriched.
This is not one of those blogs. This is not meant to be helpful. I'm just rambling.
As is common, writers find other writer friends. I'm happy to have my fair share. This also means, of course, that we throw around a lot of shop talk. The most common and frustrating can be character development.
We tear characters apart. We dissect them. The good, bad, perfections, flaws. All of it. We break these people down and decide who they are from the moment we meet them. Where do they come from? How does that affect their psyche? Who are their friends? What are their passions? What fears do their harbor or hopes that they long for? Who are these people?
For a lot of writers, the answers come with the dissection process. Questionnaires. Charts. Answer sheets. Even character interviews.
I'm lucky. When I ask 'who are these people?' ... they answer. These people come to me fully formed. There are things about them that they won't tell me. They accept some of my suggestions with a shrug and a 'whatever' but they'll reject other matters outright. I was even surprised by a sexual orientation I hadn't considered when I was writing out the description for one book.
These are people.
Most of the world can't or won't see them that way. That's their prerogative. They don't see ink as blood or the flipping of pages as a pulse. They can't laugh at their voice or cry with their sorrow. But maybe they weren't meant to.
We are not kind to our characters. We are not kind to other characters. Unconsciously, we have all created expectations for the people we read about when they are put in certain situations. It's our prerogative to expect more of them. This is their life, after all. Shouldn't they do what they can with it? Shouldn't they do more? Be more? How can they react that way instead of another? I know; I've done my fair share of being a judgmental reader and finding the characters lacking. (It's probably the only thing that will make me loathe a book, actually; despicable characters.)
What most people cannot know is that these people can/will/do show up in their entirety as a whole entity. There is no dissection. No questionnaires. No interviews or answer sheets or fun little charts. These people appear, sit us down, and open up. Sometimes it's all at once, and you're almost feverish to begin writing. Other times, it's a slow process, because they don't trust you. They don't know you, either. It's a learning process, and it can take time to get down all of the details. (And during editing, they like to crack the door open just a bit more and remind us that we missed something critical.)
I am lucky. I don't have to put in so much work when I write. Not usually. Because these are people that arrive on the threshold of my mind, catch my attention, and tell me we're going on an adventure. I'm not privy to their every secret. No one cares about their favorite color or food. When someone is telling you a story, most of the irrelevant details are left outside of it. That's how I write because that's how the story was told to me.
Sometimes, what we see as a lack of development in some books is just a lack of extraneous detail. Sometimes it's the very human flaw of realizing that some people don't always learn from their mistakes. Other times, it's because what development occurred, the character wasn't up to sharing with the class.
We all have our secrets. Our characters do, too. Should that mean we shouldn't at least learn about them? No. Does that mean that some of them will never see the light of day? Yes.
Characters are people, too. As such, we can't control them, their actions, or the way in which they do things. Sometimes the best thing we can do is sit back and record the outcome.
Other times, those interviews are really useful.
I guess, the point I'm making is: we can't control everything. And as long as what you write is true to the character you've been living with, then don't sweat the criticism. How s/he does things is not how someone else would do it. It never will be. But that's not your problem. Write the story they've lived, and it'll still be a story worth reading.