How frequently have you ever heard about being able to leave "certain" things undone. In other words, understanding that we aren't supposed to do everything. As a matter of fact someone said long ago that, "show me a man who wants to please everybody and I'll show you a man who wants to fail". Attempting to do everything is a life lived in futility.
Confucius said once, "Faced with what is right, to leave it undone shows a lack of courage." There are things once done, that can't be undone. Yes, we should only put off until tomorrow what we are willing to die without doing. The bitterest tears shed over graves are for words left unsaid and deeds left undone.
Here's a poem: