Certainly both are some good assessments as to possible reasons why the pattern would not work. Odor is a very good reason (especially if the Panty Hose were used...uhhhhhhh....soooo to speak.......or....errrrrrrr...I won't even think about the aspect of used latex lol) . Before you go to saying that all fishable realistic patterns do not catch fish (which is a very wrong conclusion), go back and consider first of all the materials used in your fishable realistic pattern; how these materials act in the water as to contributing to realistic movement or action, Color/Light/UV refraction (effect), Odor of that material, etc. What about Strike Triggers for your Fishable Realistic Pattern (what about a certain Realistic makes that Fish want to atttack ???); Legs, Eyes, Gills on Nymphs and Larva.........all these little nuances that tell that fish (even though it is an artificial) that this is juicy or even sets off the Alpha pradator Psychi in that fish. Now, lets say you now have tied that killer pattern. It now comes down to how you present your offering before the fish (even though Charlie Meck in writing about my Hydro-Psycho Caddis Larva in February's edition of Mid-Atlantic Fly Fishing Guide worked in the hardest of fishing conditions, I am sure that if this pattern had been presented poorly before all those Trout, even a skilled Pro would have been skunked). Are you getting it in that fish's strike zone ? Are you presenting that pattern in such a way that utilizes that patterns properties giving it proper action before the targeted fish ??? There are a lot of variables that should be considered. Bob Jacklin is a great Fly Fisherman, and tyer, but still could come up with a pattern that fails (but that does not mean that all fishable realistics suck), or is capable of presenting a fantastic pattern in the wrong way and getting a whiff of skunk (let's say a friend of Bob's is by him and says, "Hey Bob, you are fishing this pattern all wrong....have it rigged up all wrong....or whatever". The friend shows Bob how to fish this "killer pattern......and Bada Bing..Bada Boom,,,,,,,,,,what do ya know.......it is a killer pattern.......the whiff of skunk goes away, and what was a lousy fishing trip is a magical success). It happens in a certain water we may not know how to fish, or what patterns that may work in that certain water, certain conditions, or a place where the fish have seen it all and you have to constantly show that fish something new.........soooooooooo many factors. Even the best tyers and Fly Fishermen (& women & Kids) are always learning something new (or they should be); that is what I like so much about Fly Fishing and Fly Tying (after all these years and I am reaching the Old ****/AARP sending me spam years, and still learn something new on the waters I fish or at the tying vise).