You can't make everything perfectly every time. You can try your best, but we humans are messy, imperfect creatures, which is all part of our charm. Besides, if you never made a mistake, how would you learn? Isn't working toward mastering a discipline all about learning what not to do as much as it is learning the best practices?
So what do you do if you've sold an item to a customer and it breaks, or arrives damaged, or is not what they expected? Do you look at it as a negative judgement on your skills and your worth as a person, or do you take it as an opportunity to learn and improve? It's all too easy to take the first option, but in the end, that doesn't help your customer and it doesn't help you. If you look at a problem not as some huge horrible monster waiting to eat you but instead a new path to create something better, you'll find that you approach it with a much better mindset and you may discover ways to improve your business that you might never have thought of on your own.
As an example, around mid-year I changed silver chain suppliers. The new chain is lovely, but it has a tendency to tangle up a bit if left loose in the jewelry box. A few customers mentioned it to me that their necklaces had arrived tangled, but they were able to fix them easily. I apologized for their trouble and thanked them for the feedback, because I can't fix a problem if I don't know it exists, right? Then I set about fixing it - or in this case attempting to fix it. At first we tried wrapping the chain around a notched business card, and it seemed to work okay - until it didn't. A customer ordered two identical necklaces for her bridesmaids, and somehow, the notched card was shaken loose from her necklaces in transit, and both ended up horribly knotted. I suspect gremlins had something to do with it, the knots were so bad.
Well, her necklaces knotting wasn't her fault. It wasn't strictly my fault either, but there was only one person in this transaction that could take responsibility and fix it. So, I asked her to send the necklaces back to me and I refunded her shipping costs in sending them down to me. When the necklaces arrived, one of them was knotted beyond repair. Even after I got the knot out of the chain, the chain itself was too damaged to keep on the necklace. I wasn't about to send her necklace back with damage. That's not what she paid for, and it's not what I promised her I'd send to her when I originally made the sale. I replaced the chain section and recycled the damaged part into other things after cutting out the damaged links. But one way or another, this chain knotting problem was going to be FIXED.
I set about trying to solve the problem again, and came up with putting the chain in a small plastic baggie that I then taped to the back of the necklace card. Voila! There wasn't enough chain hanging free to knot up, and the structure of the baggie kept the chain from shifting around too much and knotting within the bag. For a few pennies of cost, a plastic baggie and a little scotch tape, my customers have the pretty necklaces they love without the worry of knots in the chain, and I have happier customers. A win-win, in my book.
While not all problems are so easily solved, and not all of them can end in a win-win resolution, approaching that problem as a positive opportunity for growth and change can make the difference between joy in your work or stress from it. I know which path I'd rather choose.