My curiosity is piqued as to why you would ask this question. Could you elaborate?
IMHO no one is perfect but we can strive for our best in many endeavors of our life. Quilterpurpledog made very good points. Acceptable levels of "perfection" are very subjective. I know I have muttered "close enough" quite often in my studio. And many other times I have ripped out the stitches to get to my acceptable level of "perfection". Of course there are many times when I was so far out of the ballpark, be it matching seams, chopped point or bad tension that I could not possibly leave it and have to rip and redo. But that is my choice. Another quilter may think good enough and a viewer could possibly never notice. One thing I will never let slide is any mistake that could compromise the integrity of the quilt such as a popped seam.
Are you planning on entering a quilt show? Again, perfection is in the eye of the beholder. Yes, if you hope to ribbon, you want intersecting seams to meet, you don't want to chop the points off triangles, you want your quilting stitches to be nice and even and tension good. You want the ditching to be in the ditch. But judges will take in the quilt as a whole before looking at these tiny details and often the overall impact of the quilt will be dynamic enough that a few imperfections are overlooked if they are even noticed.
Did someone make unkind comments about a quilt you made? If so, brush them off and continue on. Most people who make such comments are too self absorbed to realize what they have said is hurtful or they are attempting to make themselves feel better by diminishing another person's efforts or in some cases the unkind comments weren't meant to be heard by the maker (overheard at a show). Strive to improve what you can and accept what you can't.
Was a gifted quilt not as enthusiastically or graciously accepted as you hoped? A quilt is a gift of love with many hours of thought, time and effort and, at least with mine, a tiny piece of me goes into every quilt I make or quilt for someone else (longarmed client quilts). Unfortunately, many non-quilters don't realize how much goes into one when they see the mass produced, made in China, sweatshop labor ones selling at a big box store for $35.
Or are you finding that every quilt you make you are not pleased with? Are you ripping out every single seam to redo? Are you beating yourself up over not being able to achieve the same look as pictured in that magazine or pattern cover? Then perhaps it is time to learn to be more forgiving of yourself. Why pursue a hobby that makes you feel bad about yourself? It is said here very often that we are our own worst critics. If you can't learn to be kinder to yourself and your workmanship then nothing anyone can post here will help.