I like to do the same thing. I love to look at a fly/crayfish whatever, and then go through my materials and tie what I want to imitate. I like to see if I can do it with as few materials as possible.
I do look at web pages and patterns a lot. Sometimes you get ideas from just learning a new technique from part of someone else's pattern.
I encourage this improvisational tying. It keeps Fly Fishing fresh and interesting.
Bill