I think the perfection just comes with experience after you've been doing it awhile. When I made my first quilt 8 years ago, I thought I did a great job, but I got it out recently and looked at it again and was horrified at the points that did not quite meet and the big quilting stitches. I know now better how to recognize what is really good and what is not. I am generally happy with what is good enough, but I did make a Tennessee Waltz quilt top over the summer that stresses me out every time I look at it. The pattern called for a special ruler to square up the little star point blocks, but I thought I could do it without the ruler. All was well and good until I put them all together and then I saw the need for the special tool. Some of the points were waaaay off. I was and still am so mad at myself, especially as I used a favorite discontinued piece of fabric for it. Can't decide whether to finish it, throw it away, or what.