Spontaneity Vs. Error - Trust Your Gut

  I love the spontaneity of certain paintings, but some times an error occurs and you have to go back and fix something.  A lot of times my paintings come easily for me and I don't sweat them too much, but once in a while I have to put my proverbial blood, sweat and tears into a work.
  I recently painted a painting of my dad sitting outside and I loved the overall light and feeling I was able to capture.  The painting took a little over an hour and I photographed it and called it finished.  A lot of the painting is impressionistic and even my dad's face looks unfinished, but the thing is that that was on purpose and not in error.  But I later realized that I forgot to put in the upper portion of the chair behind my dad on the left side of the painting (as indicated in the image below with the red arrow).  I want my paintings to be intentional and in control even if they appear less finished.
  I'm a purest when it comes to painting alla prima and I believe in capturing the transient moment and then called it finished in order to leave the spontaneity and not overwork it.  The problem was that I was losing sleep about that missing chair part.  My style is fairly impressionistic so a lot of people probably wouldn't notice, but I noticed and it was bothering me.  I knew it was an error.
  So what I did was I set up the chair back outside under roughly the same lighting conditions and I fixed it.  It only took a few minutes and now I finally feel the sense of relief that I get when I do something right.  It's a hard thing to judge, but I knew I had to fix it in my gut and I always trust what my gut tells me.