"Perfection is the best you can do on the day".
This was quoted to me once by a yoga teacher, and I've been fond of it ever since. People seem to split into two camps; they either embrace it wholeheartedly, or reject it completely. There doesn't seem to be any middle ground with this one!
The logic is simple. If you are doing your absolute best, then perfection is, indeed, the best you can do on the day. You can't make it any better. If you really must aim for perfection, then perhaps this quote will help you to be a little kinder to yourself, to relax the rules you are living by; I suspect that they hurt you, on a regular basis.