A character trait isn't characterization. Just declaring that a character is arrogant or obsessive or showing that means little. What's important is the cause of the trait and the effect on the character's life... and the plot, of course.
For example, in Pride and Prejudice, Darcy is famously arrogant, and behaves arrogantly towards all, especially Elizabeth. The effect of this character trait is shown immediately. Almost no one beyond his old friend Bingley likes him, and Elizabeth rejects his impetuous proposal, declaring that she can't abide his arrogant assumption that she will love him back.
So the effect is shown soon (he is disliked, and E rejects him). The cause is revealed more slowly, as Elizabeth herself comes to understand it. He grew up rich, of course, and indulged, but lost his parents early and found himself the guardian of a large estate, a huge staff, and a younger sister. His arrogance, she realizes (with the reader), was a response to the many responsibilities. She also realizes that he does not act with such arrogance to those he loves when she meets his housekeeper and his little sister.
So the cause and especially its revelation become part of the progress of the plot. But more than that, this central trait is actually changed by the events of the plot. Darcy is a snob at the start of the story, making clear that he looks down on Elizabeth's family for being socially inferior. But when he begins to help rescue her wayward sister, he must interact with her uncle, who being only a barrister is far below him in social class. He changes to someone who can appreciate the honesty and honor of this man, and even defends Elizabeth and her family against Lady Catherine, the most aristocratic snob in the book.
Arrogance is more than just a character trait here-- it leads him to behave badly and so is a catalyst for action (Lizzie rejecting him), but is also a catalyst for change, as he moves beyond his arrogance to win Lizzie back.
So let's not stop with assigning character traits to characters! That might be the start, but it isn't sufficient.
What caused it? How is this revealed?
How does this affect the story events?
How does this aspect change because of the story events?
I'm also curious about how we reveal it, perhaps early, but don't necessarily show the causes right away. I think probably we'd have to show effects right away (as it will of course affect the scenes where it "appears"). But how do we hold off the cause so we aren't just dumping backstory?