Rarely are we ever wholly and completely satisfied with our creation. There's always that one thing we would change, a slight imperfection to be corrected. We see the perfect final product, but just can't quite reach it.
For you designers, entrepreneurs, creators, that feelings will always be there. A haunting thought that if you had just spent a little more time working on it, you could've made it perfect.
But there comes a time when you must let it go. Ship it. Release it. Sell it. Whatever it is that you've spent months, years creating but you're still hesitant because it's not perfect, it's time to deliver. You will always have critics, people claiming to know how it could've been done better. After all, the only way to shield yourself from all criticisms is to never create anything at all.