I've seen novels that have grown out of one story in a collection. But it hasn't occurred to me to take any of those stories and build on them. They seem very finished for me, so I don't feel like going back and dredging them up.
“I wanted to be a mechanic. When I was 14 I wanted to quit school and go work on my car. But my dad said Son, you shouldn't do that. You should stay in school until your education is finished, and when you're done, don't make your hobby your job.”