As artists, we get so involved with a piece that our brain starts to see what it wants and often will overlook the most obvious of flaws.
Here are two of my paintings where this happened.
"B's" and Smiley faces
In the painting with the plane, somehow, the dashes and dots of color I built up in the trees formed a perfect capital 'B'. You can see it dead center in the detail photo (2nd below). It wasn't until I was looking at thumbnails of the painting on my computer that I noticed it.
In this painting, done plein air, the tangle of roots and dead branches at the base of the fallen tree formed a pretty clear smiley face, complete with a long nose! It looks like a character from the Wizard of Oz.
Maybe, there is something else happening here...some larger code being delivered through me over the course of my painting career. Hmmmm....just saying :-) Anyway, fixing these was easy enough, you just hope you find these things before the painting makes it out into the world!
Of course, once you find a flaw it is the ONLY thing you can see from then on. It SCREAMS at you to be fixed!