I won't tolerate much in construction flaws if I'm able to fix it, but what I am more tolerant of is the design mistakes that I realize I've made, after the top is completed. I would say all of the quilts I've made thus far are flawed in some way (with regard to color, contrast, etc.), but I think that because I've invested so much time in thinking about them and making them, I tend to grow fond of them anyway.
As for construction, I believe my standards have risen along with my skills. My early quilts are much less precise, but I can tolerate that because I know it was the best I could do at the time.