". . . listen to others, even the dull and ignorant; they too have their story."
I would actually go further to say that "dull and ignorant," like beauty, is really in the eye of the beholder. Each and every one of us thinks our experiences are exciting (or, at least I hope we all do), it's just a matter of getting the right audience to listen.
As a writer, I find it easy to be that "right" audience. A few simple and well-timed questions can make people open up about their lives. Many times, I don't even have to ask questions. People will often just walk up to me and proceed to tell me the most random things. I guess I have the sort of presence that makes people comfortable to share personal details.
I once had a man approach me in a Walgreens around Easter. He asked me if I thought he should buy peanut butter Easter Eggs, then proceeded to tell me how his mother never let him buy those kinds of things, as well as some other issues he had with her. This conversation went on for quite a while, until I said I had to get back to work. Back when I lived in Chicago, I even had fellow bus passengers tell me stories you wouldn't think to tell a stranger. In most instances, there's never any provocation on my part, they just start sharing.
It can sometimes be frustrating to have strangers confide in me as if I'm their therapist, but there have been times that I've found their tales to be quite interesting, too. Ultimately though, the writer in me stores away little tidbits from the experience for a future character each time something like that happens. Maybe I'll "steal" the person's hand gestures, or nervous twitch they don't even realize they have. Maybe the color of their eyes will be so striking that I'll try to write a vivid description down in my trusty notebook for future reference. There was an elderly woman whose face and countenance struck me so much that I immediately created a character and entire life for her after we’d parted ways. I have no idea if the story I made up about her was even close to the real thing, but it didn't matter. It was just a wonderful moment of inspiration.
How many of your characters have been inspired by strangers you’ve encountered?