The day before "Done'' is terrifying, that's why it's very common to see people sabotage themselves by avoiding to finish and launch their project.
You're faced with one, or all of the following 3 FEARS:
What Happens Next?
What if the product you've spent so much time and money creating doesn't sell?
What happens when you finish the book, and you have to receive judgement and criticism?
Or, if it's well-received and it's gone viral, and suddenly all the spotlight is on you, how well will you handle it?
You're no longer safe in the comfort of your small office being by yourself. You're exposed, vulnerable, and facing rejection.
Thinking that you might fail can keep you from finishing your book and remaining the eternal writer or student. Even the all-time best-selling Harry Potter books have 12% negative reviews. One of them says, "The worst book that I've read in my entire life."
It Won’t Be Perfect
Fear that the end won't be as great as the rest of the series. I've heard people stop watching "Breaking Bad" just 3 chapters before the season ends, because they don't want to be disappointed.
The truth is that no one knows the outcome. Huge Hollywood movie productions with A-list actors have bombed, while independent low-cost movies get all the accolades.
The Fear of What Now
This is very common with kid actors that are growing up, or top athletes that have reached their 30's. Your identity is tied to your career, and you fear who you'll become once it's over, how will you transition to your life's next stage?