I’ve had this same problem with one of my products. If I know the fault is there then sometimes I just cant bring myself to sell it on!
If it’s bothering you that much I found that if I just put the particular item to one side and carried on with other orders, then went back to it later I would know what to do with it. I ended up taking one of my scarves on holiday with me to unravel and knit again so I could finally list it in my shop! Another time this happened I was too busy to spend time picking it apart and re-workng it, so I kept it for myself!
Sometimes you just have to wrestle with the perfectionist within. I hope we’ve helped you!