I remember reading that our brain doesn't know the difference between an actual event that is taking place in real time and something that we remember that brings up great feelings from the past. To our brain it is all real time.
I try to remind myself of this when I am holding on to something that brings sadness, fear or anger. Oftentimes the tapes that I play over and over in my head are ones that put myself down for not getting something done. Or, not doing something "good enough." When in all reality, if I were watching someone else doing the same exact thing - I would think they're wonderful!
Here are FIVE bullet point differences of Doing Your Best vs. Perfectionism (click on image to view larger):
This is from the Ensign article "What is Perfectionism" by Cecil Samuelson.
It is quite amazing the words that stand out in each category. I think if I want a tape recording in my head, I would much prefer the one on the left!