Sometimes a trait I find annoying in a person could make a character onstage very interesting. As an example, I'm thinking of someone I know who has a tendency towards nostalgia. Nostalgia on its own isn't such a bad thing, but I feel like this person is so fond of things were during childhood, that telling the anecdotes becomes the subject of all mental focus, replacing opportunities to continue growing and learning about the world. Precluded are any chances for thoughtful reflection, analysis of why things may be different now, or consideration of whether the changes are for the better or possibly a sign of decline. As a character, however, such a trait offers many possibilities, perhaps as the sole remaining keeper of some precious bit of information, or the one who reveals what all others in the story have long forgotten and need to be reminded of to keep their humanity alive, or simply as a witness of times past passing on the torch to the next generation. How else could this idea be utilized?
This way of looking at things helps me look more sympathetically on others. And it reminds me to look at the world as a source of creative inspiration.