In writing as in life, character development takes time. It's a journey of discovery, not a one-time, one page description. And it doesn't happen in a vacuum (or a chapter), but rather by meeting and beating challenges as the story unfolds.
If nothing "interesting" ever happens, nothing is learned or gained.
Sometimes events that shape a character are unexpected - even to the author. They pop up out of nowhere, and somehow, sense has to be made of them in context of the larger story. It's not necessarily what the "event" is, but what the author does with it that matters. What might work for one scene, might divert the tale away from it's intended outcome. That can complicate the plot, especially if the goal is a neat, happy ending.
Writers love conflict. Thankfully, in writing, I can choose to edit things out. But in life, it's all about the resolution.