Matt, there's an old song that has a refrain, "when you've been eating steak for a long time, beans, beans taste fine." Its verses ask things like, "why do you go out with an older less than gorgeous woman now, when your previous lovers were young, blonde, and beautiful?" Each question is followed by the refrain, "When you've been eating steak for a long time, beans, beans taste fine." The idea is that we all seek variety. Now, if I lived on the Delaware, The upper Missouri, or the Henry's Fork I might not seek out small streams as often as I do now. And if I lived in Labrador I might not go looking for tiny brookies in step-across streams, so I'll also have to admit that location, location, location (along with limited time and funds) is part of the reason I fish small streams for small fish at times. But I sometimes have the choice of fishing for bigger stocked fish or small wild ones, and I take the small wild ones most of the time. And I'd also say that the beauty of the streams, and the birds and flowers along them also draws me back into the less-traveled paths. Then there is the challenge of casting in close quarters, finding a way to deliver a fly when it appears to be impossible. So the reasons are complex for me. I'll close now to let other small stream fans add their reasons.
"He spread them a yard and a half. 'And every one that got away is this big.'"
--Fred Chappell