1. If something is not perfect it is worthless.
2. My performance must be perfect or else it is awful.
3. If I am not perfect then I am less worthwhile.
These rigid beliefs will most certainly make you unhappy and perhaps downright miserable. Opt for a more realistic, sensible, and flexible view. I call this sensible view the "good enough view." Strive for a good enough performance. Here are some examples of this approach applied to the above beliefs:
1. Even when something is not perfect it can be worthwhile. Perfection is an illusion. Demanding perfection is a great way to be unhappy. Perfection is an idea that does not exist in everyday reality. I would prefer perfection but alas the world, I and others are imperfect and demanding perfection is a great way to be unhappy.
2. My performance does not have to be perfect. When it is not sufficiently good I will strive to improve it but it is not awful or unbearable that my performance could benefit from improvement.
3. Even if I am not perfect I am not less worthwhile. Being human means being fallible and imperfect. I can accept me even if I am an imperfect person.