If you are human you make mistakes and this includes mistakes in woodworking!  How you correct the mistakes demonstrates artistry in your craftsmanship.  Many people call these corrections design changes!  As you gain knowledge and skill you learn how to fix problems.  If I cannot repair an error then I prefer to accentuate it by making a radical change to the design, such as, incorporating a different species of wood to draw the eye to that area.  Therefore, it looks intentional and unique.  I had one friend tell me he spends more time showing his students how to correct errors than teaching the original lesson.  How you correct the errors not only affirms craftsmanship but personal character. Do you make quick, substandard repairs or do you turn your mistake into a quality design feature?  If your intent is to fix the problem only until the work is “out the door” or delivered then are your fixing the problem?  You are only passing the situation on to someone else.  When I do business with an individual or business I always pay attention to how they correct their mistakes.  This dictates if I continue to do business with them or seek other options.  By permanently correcting your mistakes you are showing your craftsmanship but building your character!