It's tougher to start a story with a protagonist who's downhearted and pessimistic. In her excellent book The Magic Words: Writing Great Books for Children and Young Adults, Cheryl Klein likens the experience to listening to a negative person at a party who goes on and on about their bad luck and how it never changes. Who wants to spend time with that person? She says negative, defeated characters are unappealing. If you start a story with a protagonist who's downhearted, it's vitally important to show they're resilience and assertiveness. Immediately! And humor counts double in this story.
So, guess who starts every book with a dispirited, passive person?
Yep, that would be me. My muse NEVER imagines characters who wake up on the right side of the bed with a sword drawn to vanquish their enemies. In my critique group The Skyway Writers, my critique partners know I always want their eyes searching for the passages where my character lacks assertiveness. They help me see when she's reacting instead of acting, passive instead of active, finding problems instead of solutions and embracing defeat instead of believing in victory.
I think most writers tend to pen protagonists with personalities that echo their own. If you're not a witty and daring optimist, that doesn't mean you can't create appealing characters. You just have to dig deeper, find the parts of you that believe in miracles and have the courage to overcome the most dreadful events. Write the character you hope to become!