When we sit back and consider the conclusions that people often draw about themselves or others, it becomes more evident that errors in measurement creep in, unnoticed and unchallenged. Face-value assessments are accepted as truth. This is damaging to human beings on many levels. Here are a few reasons why. First, these errors in measurement fail to represent the totality of a person's nature and potential. Second, a subjective position of value is often taken as a result. In other words, my measurements are wrong and I judge my measurements as being good or bad based on my current worldview (even though they are wrong, to begin with).
A human being, who happens to be a professional footballer, for example, may perform outstandingly well until they, in a very human way, miskick a penalty. Very quickly that footballer could assess themself as useless, and worthless because they couldn't perform with precision "when it mattered most". This self-measurement is often interpreted as a measurement of their totality, and have extremely detrimental consequences on their ability to live with vitality and continue to develop their football expertise.
This footballer's philosophical conclusions lead to much anguish and anxiety about their future, but their conclusions are wriggled with errors. All that has happened is that they have witnessed their own humanness, a momentary action, a snapshot of external expression. It is, therefore, a complete mistake to rate their totality by measuring only one moment. To measure a human being in this way is like measuring an ocean with a six-inch ruler, it's simply impossible to do so with any accuracy.
The second error is potentially even more problematic. If that footballer then judges their value, their total worth against this error of measurement they will find that, more often than not, they will judge themself, in their totality, as worthless which has a detrimental impact on their ability to remain energised, resilient, and effective.
To counter this it is better to first recognise that the infinite cannot be measured by the assessment of a single moment, and to recognise the uselessness of assessing one's self as totally good or bad in any situation. Instead, recognise, that there is a difference between your internal self, and your external performances, the former is the cosmic miracle of life, and not up for measurement, and the latter can be assessed as effective or ineffective, helpful or unhelpful towards a particular goal and learned from as part of an ever-present desire to meet ones potential.
Note: To inform my writing I have drawn on the work of Ellis A., (2005) The Myth of Self-Esteem. New York: Prometheus Books and Hartman, Robert S. (1967). Formal axiology and the measurement of values. Journal of Value Inquiry 1 (1):38-46