I have been making things for a while now - a bit over a decade. I have learned from success. The things learned from success were limited. I learned what succeed but not what could have. Maybe if I did something differently I would have sold 5-10% more.
I learn from failure. Maybe it's a small failure. At Nock Co. we have a product called the Fodderstack. This is not our best selling product, or our third best selling product. It is my the product I am most proud of. This pattern, how it functions and what it means to me proving my ability holds a huge amount of weight internally. We have shown this product to large job shops and they couldn't figure out what we were doing to make it function how it does. I figured the pattern out not by drawing something on the computer, but by cutting and sewing 6 or 12 versions of it. The process is so exciting. I talked with Brad for two minutes about making a sleeve for a 3x5" notecard and I was off. (Come to think about it this is how Nock Co. happened too).
Seeing a design go from spoken word to sellable product is a joy that is hard to describe. Seeing my son develop from being an infant to being a walking talking human has been amazing and that is similar to the life of a product for me. Going from an idea, to seeing if we can make it, how will the finances work, the talk of what it will look like, and then the day it finally arrives. The next part is amazing, you see it live. The product is used by others and introduces feedback, praise and life. Things are done to your idea that could be categorized as vulgar - which is amazing.
On the other hand I have made many things that will never be seen. I have thought of things that never seen pen and paper. I never know if it's a mistake that I don't sketch, talk about, or do a quick physical prototype of a...whatever. I like to think that I can vet bad ideas mentally so I don't waste time. I am not sure if this is reality but I know that some things fail at step 1 to make room for more step 1s. I never fear failure but I do look forward to what comes from it.