Every fly has four triggering devices: size, shape, color and behavior. The primary trigger draws the trout’s attention to the fly the others are secondary triggers,
A knowledgeable tyer emphasizes the primary trigger then considers the secondary triggers. Trout look for what’s right not what is wrong. It’s better to skip a secondary trigger than make a mistake.
A refusal is when a trout sees the primary trigger, often the silhouette, approaches, then sees incorrect secondary triggers and refuses the fly.
I earned my living selling flies at the Little Lehigh Shop. The flies that caught the most trout, the best sellers, were easy to tie and looked the same from all angles. Real flies don’t tumble, imitations do, beautifully tied woven bodies showing all dimensions of the fly instead of one as in a natural drift. The angler needs to evaluate the natural then make sure his fly captures the primary trigger. The secondary triggering devices should also be present if accurate and not obscure the primary trigger. Selectively feeding wild trout are looking for what is right not what’s wrong. If you’re getting refusals, (assuming your drift and tippet sizes are correct), make adjustments to your fly. Legendary Pennsylvania fly fisherman, Charlie Fox
played “a game of nods”. If a fish would refuse his pattern, he would start trimming his fly. He would continue to adjust his fly until the fish took it. From my book, Thoughts. Observations and Advise of a Trout Bum