Perfectionism is not always a virtue - I said this to a client when we had to overlook a few extra scratches, dings and contractor errors and she thought that was a 'great saying'. But what is perfectionism? It is most certainly different for everyone. If you feel yours is causing you stress, lighten up.
In this dining room, it may be very intentional that the table cloth hangs sloppily and that the track lights are off-center - what are those tracks doing there anyway? But if you try to imagine the person living there, you may see a relaxed individual, overlooking imperfections, perhaps labeling these imperfections as patina or character, and just enjoying the ease of this formal space.
So, lighten up! Take this rule into your decorating and you're sure to be able to relax about it all and just enjoy that oddball chair that is sentimental but doesn't match, or that ding on the cabinet because you remember when your best friend's son took a hammer to it. Let your house tell your story.