On the night the angels appeared to the shepherds to announce Jesus' birth, some of the shepherds missed the message because they were looking for dust on the angels' wings.
There are people who are called to be flaw finders, i.e., critics. They can't seem to help themselves.
I would never tell anyone about a flaw in his/her quilt, even if I saw it, which is quite unlikely since I usually can't find the flaw when someone points it out.