This means many different things to many people and for a variety of contexts. These descriptions of a "good" fly are just my opinions and are not ranked in any way nor are they influenced by actual fish thought. Certainly, good can mean a fly that fish respond to by taking it either for something to eat or as an interloper into its territory. Typically, a fly that imitates fish food is said to have a certain "bugginess" to it. Bugginess means to me that the fly looks alive and imitates or suggests normal insects and even bait fish that the prey fish encounters on any given day. These flies typically have a rather shaggy look about them and have parts that suggest insect/baitfish legs, gills or fins flailing away as they drift or swim. These flies are often "good" flies. There are those flies that don't even remotely look like potential food, at least to our eyes. Fully dressed flies and brightly colored Steelhead, Salmon and Bass flies often just look like an artist dropped his palette onto a hook. Over the years, the topic of why fish react to these sometimes gaudy flies has been debated by better thinkers than I and the arguments still persist. It is probable that some of these flies look like potential prey that is fleeing the territory of the predator fish. Fish may also see these flies as interlopers and strike to protect its territory. Others may just ever so slightly resemble something that might be edible that will tempt the fish to "taste" it. That the fish do strike these flies is enough rationalization for me. These are also "good" flies. A good fly may also be said to be a durable fly that also exhibits the above traits. What achieves this are things like wire or tinsel ribbing to bind hackle or protect otherwise fragile bodies. Other armaments can also be twisting wire or thread with herl to make a kind of chenille, coating floss bodies with head cement, adding epoxy to heads of flies and so on. Again, "good" flies. A good fly can also be one that has stood the test of time. For a pattern to endure and be used decade after decade, it must be effective. Spey flies are an example of this. They originated in Scotland some hundred years ago. They caught fish then and continue to this day. Another meaning of a good fly can be the care and skill that it has been tied with. A common Adams with the often elusive tiny smooth head, tapered body and upright wings that comes to rest with the desired three point landing (Tail, bend of hook and, hackle tips) is definitely a good fly. Good is also the hallmark of a neatly tied and well-proportioned fully dressed fly. It exhibits even ribs, a smooth floss tag and body, wing and veilings that sit upright with no twists, a smooth, glossy and tiny head are just a few of the characteristics of a good/well tied fly. Good flies are also those that are the pride of the Tyer. They may not be perfect in every way but are the best the Tyer can do and they are justifiably proud of their creations. We've all tied these flies during our tying lifetime. As we tie flies year after year, we develop better skills and our flies improve. We were all puffed with pride when we caught our first fish with a fly we tied and many of us still recall the experience years later with a fond recollection of where we started in relation to where we are now. I have a few of the flies I tied in the mid fifties as a lad and at the time, those were the best flies the world had ever been seen. At least that is what I thought at the time. Now however, the survivors are some of the homeliest flies I have ever seen! They were "good" flies at the time and in some special way only evident to me, they remain "good." When we hear someone else talking about a "good" fly, he/she is discussing it based on their biases and we listen and view the fly from ours. The bottom line is that what makes a fly a good fly, can and will always mean many different things to different people. Frankly, any fly that induces a hookup with a fish is a good fly! ~ RL