It seems to me that if you don't eavesdrop on other people's business you can miss out on a lot, especially if you are a writer. Years ago at work I overheard two women talking about shaving their legs. One said to the other, "If I had legs like yours, I'd get a guy to shave them for me."
Then yesterday in a grocery store I saw a man of about 35 walking with one arm gripped tightly around the shoulders of a girl of about 13. As I passed them, I heard this:
Girl: "Why did you hit me?"
Man: "Because you needed to be hit."
As innocent as it could have been, that snippet of conversation disturbed me. There are certainly a lot of blanks a writer's imagination could fill in.
Do you eavesdrop? Do you find it grist for your fiction-writing grindstone?