This is a strange thing to discuss, but I've had conversations with various people about how people behave.
I want you to consider two ideas. First, is your character alive, or are they boring and waiting to die?
And second, do you consider your character to be a living entity?
Believe it or not, these two things are related.
A friend of mine lives in a town (much like where I now live) where the locals stay to themselves, never do anything fun, and basically are waiting to die. They might do a few things, but they rarely travel, rarely enjoy any new situation, and don't take risks. Those characters are boring with a capital B. Make them take risks. Give them life.
To take this further, a writer has to bring the character to life for the reader to keep reading. To do this, that character has to live in the writer's head. They take risks there and talk to the writer.
I've had more than one conversation with other writers about characters taking over their thoughts. The character has conversations with the writer in the weirdest places, like the grocery store, etc. Is the writer crazy? Nope. That's normal. That's how a writer gets to know the character--how they think and how they live. The character comes alive like that.
I've thought of characters coming together from various books of mine, in a conference in my head. Those characters had a lot to say to each other. It was hilarious! Some of them even clashed, wanting to take charge.
So does your character live in its environment and in your head?
Have a great day!