As I age more some things take more time and are more challenging. My daily cognitive affirmation is as follows:
"Have the serenity to accept things I cannot change;
Courage to try to change things I can (and learn from my "attempts" (I don't call them failures)); and
Learn the difference (only by trying over and over again using different approaches can I do this)."
I make no demands on my past, myself, others or the world. It is as it is; therefore, it should be as it is. I can work on myself and look forward to getting better results. I accept that I have a good "heart", "existential self", or "soul (until we die we will not know whether it is immortal or mortal)". However, I know I am fallible and will forever be fallible, make mistakes and strive to correct these mistakes. In words of Martin Luther King, "Hate the sin, but not the sinner."
I use the stoic principle of accepting one unpleasant reality every day, but in a flexible way saying, "For the time being I cannot change this situation, but I can from time to time work on trying to do so."
Example, "So far I have not achieved my goal of losing significant amount of weight, but I have not given up trying. I am still in there fighting and I have a number of new ideas to try out how to do it in the future. I do not down myself for not having lost as much weight as I want to, nor have I given up effort and hope. Any progress is commendable."
Same goes for my dysfluencies in speech. I strive to talk better, but time to time I have some dysfluencies. I can see vast improvement in both my speech and in negative feelings about stuttering. I strive not to feel badly (feel shame, guilt or anxiety) when this happens and mostly I have been able to be my best friend and forgive myself for being fallible. I know that perfectionism is counterproductive, so when I succumb to the false goddess of pride for having made a perfect presentation at the university, I privately smile at myself :-) and remind myself that perfect speech does not make me a better person. However, more flowing speech with less negative feelings (e.g. guilt, anxiety, shame .) about my speech sometimes helps me to get more of my practical goals.