Neutral colors like olive, tan, brown are best for normal day time and normal water color. Bright colors often work best in bright light. Sometimes a bright and a dark mixed is very effective. I think that through time and natural selection, life forms will often change colors to match conditions. My point is that many life-forms will often appear to match the surroundings in which they live or they won't be around too long.
Price shows patterns from all over the world.
I was fascinated with the large Welsh, Irish and British wet flies. These conditions are very similar to our dirt rich Midwestern lakes full of silt and mudddy bottoms. I started mixing man made materials and colors. What followed were the wet fly designs. Another consideration is size.