I also think that in high-pressure situations the fish do get used to, and start to ignore both certain colors and certain styles of flies/lures. Maybe some of what you experienced with the purple color, Krash .....
I believe you are correct about that.. Same thing goes for other conditions, like boats passing by. Out of Holiday park most of the bass fishing is done in the canals and its like I-95 out there, boats flying by throwing 50-60 mph wakes in a 60' wide canal never slowing down to pass another boat, and it does not phase the fish on the very next cast while you are a rocking a fish will slam your bait... but many other places you have to sneak up on the fish and a boat flying by will spook the fish for quite a while. The fish are just conditioned to continue doing what they were doing without notice when boats blow by,
Krash, up here on the Mosquito Lagoon, it's becoming very difficult to catch the monster redfish (30" +) with any kind of artificial lure or fly. You have to realize that most of these fish have been caught multiple times, and they learn. So now it's very difficult to find them in the shallows in the first place, get close (will spook at any electric motor sound and/or banging of paddles on hull), and many folks now are opting to use bait as all artificials get refused.
AP, for real.. I thought you could catch Reds in the lagoon on anything. It sounds like the B-Bay Reds might have moved up to the lagoon they hide even if you text your buddy you are going fishing tomorrow.
Old fugger with a bad heart, who just wants to fish