I would think that the best way to define perfection would be in relation to universal standards. A perfect score would be a 100%. However, if you received 102% for extra credit, it would still be perfection based on the universal standards of getting all the answers correct that can affect you negatively.
Thinking of what the person stated with the duck and tree example, language is used as a universal standard so that we can communicate effectively with each other. Although language is a universal standard of communication for a society, there is no way to actually achieve perfection in communication because there may not be a word in a given language to describe something completely as a person experiences it. There can only be perfection against the universal standard of language, but not in communication itself. Likewise, there can only be perfection in the universal standard of 100% of points in a course. There is no way to have absolute perfection in knowledge of a subject area. How do I know that? There is no universal standard on what knowledge is. hahaha
If a person chooses to disregard a universal standard as not being relevant to their life, then that just means that perfection related to that standard is not important to the individual, but the perfection still exists regardless.