As an author you should go back and read your own work from time to time, preferably a year or more after you wrote it. After your work has “settled” for a while, you can see it more as your readers do, be more objective, identify areas where you need to improve, or in other cases amaze even yourself with your skill.
Don’t cringe if you find your former work far below what you now produce. Skills evolve with practice and time. This is true whether it involves playing a musical instrument, dancing, participating in sports, completing math problems, or expressing yourself in writing. Seeing progress should be encouraging, though in some cases you may want to go back and rewrite it to bring it up to your new standards. This is why some writing instructors advice throwing your first novel in the trash and considering it tuition.