Ideas?

It's a pretty consistent question that we writers get all the time. But just walking around yesterday made me realize how ideas are just everywhere...and character. Like there's the guy in my neighborhood who rides his bike backwards, all the time. Sometimes he's just going in circles. Why? Is he proud of himself? Did he never learn the proper way? Or is it some magical thing where if he goes fast enough he'll go back in time? See how ideas can just spring out of something you've read. What about the other guy who's always walking his dog? Or the blind woman with the seeing-eye dog? She's out every day rain or shine. I don't know these people, but I know that I can make up stories about them...and maybe at some point one of those stories might end up in a book.