Increasing the quantity of something which is initially good will always lead to an excess?

Question

Take this sentence from a psychological article on wikipedia about the comfort zone:

However, White (2009) also observes that if the work of Robert Yerkes (1907) is considered in which he reported 'Anxiety improves performance until a certain optimum level of arousal has been reached. Beyond that point, performance deteriorates as higher levels of anxiety are attained', if a person steps beyond the optimum performance zone they enter a "danger zone" in which performance will decline rapidly as higher levels of anxiety or discomfort occur.

In this case, scientific evidence are suggesting that anxiety initially improves the performance but when it raises it has the opposite effect. Since that the word "excess".

Sometime is really less intuitive that a raise of something which is initially good will become un-optimal.

An excess of perfectionism could lead to OCD and to an anankastic disorder. See: Is perfectionism related to OCD?

But it's very less intuitive. Starting from this consideration, at an intuitive level, I would guess that every good thing when applied and applied will become suboptimal.

(*)The concept of "too-much" and "excess" is already bound to the consequence and applies only when there are negative consequences.

Is it a generalizable result that very often the complete lack of something or the excessive presence of it can lead to problems?

Answer 1

It's a pretty huge question due to its generality, but at that level, it's probably safe to say most things can produce problems in excess. The only specific things you've mentioned are anxiety and perfectionism as far as I can tell. More specifics would help generate clearer answers, but @Prasanta's is good for anxiety, and your intuition resembles theory (if not necessarily reality) about the relationship between perfectionism and obsessive disorders.

More broadly, I recall reading a chapter (not sure which, but I'd guess it was David Buss') in John, Robins, and Pervin ⁽²⁰¹⁰⁾ that argued personality traits in general tend to vary naturally because this increases the adaptive versatility of the society that contains individuals with different talents, responsibilities, and not all the same vulnerabilities. This is similar to the immunological theory that if all members of a species shared the same vulnerability to a certain pathogen, that pathogen could wipe out the entire species if it arose and spread. Individual differences protect the species (or the society) by increasing the likelihood that some individuals will be resistant to sudden selective pressures and survive in the case of catastrophe. The principle also works at less extreme levels of pressure: e.g., having some individuals high in neuroticism may improve the society's responsiveness to subtle, looming dangers that necessitate preventative effort well before the danger takes consequential effect. For example within this example, people who worry excessively about government conspiracies help ensure that the rest of us don't grow complacent about a lack of transparency in governmental functions. In a more evolutionary context, hypervigilant worrywarts would tend to help protect their neighbors from predators.

Given these selective pressures at the societal level that promote variation, some outliers may arise naturally. Even though neuroticism tends to be psychologically unhealthy, neurotic individuals may adapt optimally to certain circumstances, especially threatening ones. In this sense, "excess" depends on context: many excessively strong traits in normative contexts may be adaptive in rarer contexts. It's even conceivable that in certain circumstances, one could be excessively average! E.g., if a socially polarizing issue divides people into violently conflicting groups, having no strong leaning could endanger moderate individuals by making them misfits in either polarized group, especially if group protection is crucial. Such scenarios are probably applicable to a minority of selective pressures though, so your intuition about polar extremes being more problematic is probably more generally applicable, if somewhat unfalsifiable.

_{Reference
John, O. P., Robins, R. W., & Pervin, L. A. (Eds., 2010). Handbook of personality: Theory and research. Guilford Press.}

Answer 2

I think what you are getting at is the concept of "stimulation". It has been shown in literature that individuals have varying "ideal" levels of stimulation and this can be measured using popular scales (Zuckerman's Sensation Seeking Scale being one of them). The stimulation - performance relationship can be thought of an inverted U-shaped curve with a peak stimulation point. If you are far to the left of this peak point, you feel bored and seek varied behavior to increase stimulation. If you are far to the right of this peak point, you feel anxious/restless. Both these states could potentially be detrimental to one's performance.

Ref: http://en.wikipedia.org/wiki/Sensation_seeking