Rob,
I once had the pleasure of meeting Tage Frid and attending a brief teaching lecture in which he purposely made a poorly fitting handcut dovetail joint and then demonstrated how to fix it so that few would ever discover the error. He shimmed the loose fitting sides between the associated pins and tails with veneer stock, which he left standing proud of the joint and hammered to smash the veneer into the joint to fill it completely. He said that the difference between the pros and the amateurs is that the pros know better how to hide their mistakes.
I make plenty of mistakes. If you check, most commercial pieces of furniture have some mistakes that you can find. Ditto for custom made pieces, too. But it takes a skilled woodworker to find most of them, most people will never notice, and those mistakes generally don't detract much from the overall positive attributes and value of the piece.
Dave R.