I had a board off a shaper that I loved - a 6'6" - I was so impressed I took in a 6'10" and asked for his interpretation of the 6'10" (which I still have and it is one of two "magic" boards I have had).
The 6'9" I got wasn't as loose as the 6'6" or 6'10", didnt paddle as well as the 6'10" and felt more like my 7'2" but without the paddle power. It just didn't do anything different or better than boards I already had. I sold it last year to a bloke who loves it. It's only the 3rd board I have ever sold.
Another board I got made I sat on the shaper's shoulder as I asked him three times from the final shape to lose some rail volume. The second time I asked he looked at me and said, "you can take it away, but you can't put it back. Are you sure?" Thinking I knew stuff, I insisted. Now, the board has never let me down. It is the board I have had one of my biggest and best barrels on. But the rails just feel weird. Like everyone I sit there out the back and fondle my board and it doesn't instil confidence in me as I feel it. It's a gun, so feeling confident and having faith is pretty important.
So my "dogs" have been a result of input from me.

Having said that, I have never had a board off a shaper under 50 - grey hairs count in my book as they have made most of their mistakes before me.
Out of the last four boards I have bought off the rack, 2 were crap, one did exactly what I wanted but snapped after 18 months, and one was far far better and more versatile than I expected and is one of my current go to boards (and a rare off the rack board with 6 X 6 X 6 oz glass

).