Take your proudest accomplishment. Is it conceivable that someone can come along and improve upon it, whether from a process standpoint or the end result?
Everything can be improved upon, including your very best work. The idea that people can achieve perfection is a myth. Is there anything man-made that can’t be made better somehow, or anything in nature that is incapable of evolving?
It can be freeing to approach an effort with the mindset that you are fulfilling your responsibility to improve upon something. What are you adding to a larger effort? What is your contribution, alongside others’?
It can be freeing to approach a project knowing that you are showcasing only your particular brand of skill. What can you do that is what no one else can?
You are incapable of producing perfection. Put out your best work, yes. But your best will never be perfection. So you might as well get on with it!