It is quite a skill for a writer to look at their work and know what is working and what isn't without judgement. This is also a skill worth practice and development. Even the "A" list writers struggle. Writing is a process . We take the good with the bad and know that through the hills and valleys as long as we push on we will arrive at our destination.
A ratio of failures is built into the process of writing. The wastebasket has evolved for a reason.