My favorite fly has a very long name ("Wilcox's J.C. Special Pheasant Tail")
It is big and ugly, not delicate and elegant, and I can't really see that it matches any hatch I know of. But, aesthetics aside, it really works well.
I originally bought these as strike indicators for when I was fishing a dropper nymph rig. I began getting so many hits on the "indicator" that I began fishing these stand-alone dry flies.
I used to tie on a parachute adams as my go-to dry fly. This "ugly bug" as I calll it has now become my favorite.
As an added bonus, the big high-vis parachute on these things means that I can see the fly better on the water.