This is huge, and it's something that hampers all kinds of writers.
You focus so much on being perfect that you end up not being able to write anything at all. The search for the perfect words, sentences, analogies, and rhymes leaves you in a state of paralysis.
Trying to be perfect takes you out of the creative mindset and leaves you continuously critiquing your work.
When you write, focus on nurturing your creativity rather than being perfect. Let the music and lyrics come to you as they are.