I've been noticing posts across several writer's forums and sites where writers ponder giving up because the perfect words won't come out. It seems like people believe they weren't meant to do this is they cannot emulate John Donne, or Lord Milton, or whomever their writing hero might be. Fear not, fellow, writers! It's completely okay to fail!
I'm not trying to lay any blame on anyone. Quite the contrary.
We all hit speed bumps where we scrunch our faces, think so hard we smell smoke, shake the ever-living-daylights out of our muse...
And what hits the page is pure, unadulterated, unmitigated, foul-smelling trash. I have a page or three that I keep locked and hidden because I'm afraid dumpster-divers will read it, and that the smoke of burning them will stink up the whole area.
We need those moments, though. For a couple of reasons. Primarily, I think, we don't get better by playing safe. We find our limits, and expand them, by reaching outside those limits until we fall down. Then we get up, dust ourselves off, and we go there again. And again. Eventually, we don't fall down. Further on, we might even get good at that challenge.
This is true of athletes, of professionals, of hobbyists, and it doesn't matter whether it's a physical activity or an intellectual one.
Be ready to admit, "I can't." But understand that it really means, "I can't, yet." Almost every time, the difference between those who succeed and those who fail is that the winners got back up and tried one more time than they failed.
Find out the history of Silly Putty. Of Post-It Notes. Mistakes. Pure, tragic failures, until someone went, "wait, I can..."
The telephone was a failure... until Alexander Graham Bell spilled acid on himself.
Arthur Dent was a failure until the Vogons... uh... wait... that was a story.
Remember that you enjoy this, and even in failure, what you're creating didn't exist until you created it. That's amazing stuff. So, yeah, permission to screw up is granted. And, hey, you never know. Maybe that horrible drama you just wrote is actually genius comedy!