Continue to fill a pail of water after it is full, the water will be wasted. Excess of light blinds the eye, excess of sound deafens the ear. Too much is always a curse; most of all, in wealth.
The above lines were often recited in my school during morning assembly. Obviously didn't give much consideration to them then, let alone understanding the meaning. However, over the years, learnings from various walks of life and a fair bit of experience unveiled its meaning. A very eloquent and familiar term across several disciplines, academic and otherwise, is 'equilibrium'. We refer to it in Chemistry (chemical equilibrium), Physics (thermodynamic/ static), Economics (market equilibrium), Biology (homeostasis) and so on. Equilibrium is usually the most optimum position that all objects/forces naturally tend to. Nature is inherently designed to maintain a balance of opposites, or what we call a 'dynamic equilibrium' wherein two opposing forces cancel each other out and maintain a stable condition. From the smallest unit we know to exist independently: an atom, to the largest we can conceive: a biosphere, every system looks to reach and maintain stability by cancelling out excess opposing forces.
The human body, with its sophisticated mechanism of functioning, is designed to maintain equilibrium at all times. This is the reason we are able to maintain an average internal temperature of 98.6 F no matter what the temperature outside. This condition of homeostasis is absolutely essential to the smooth functioning of the body. When the body is faced with stress (caused by actual or perceived threat to well-being), it is basically thrown off its state of homeostasis and it sets off a series of hormonal and neural reactions. Continuous exposure to this stress leads to resistance or adaptation and further sustenance of the stress, without periods of relaxation or rest, causes exhaustion. Stress can be 'good' or 'bad' depending on its effect on the person going through it. Some degree of stress is inevitable in life and avoiding it completely can be equally harmful. Until one is thrown off from a zone of comfort, they do not develop the capacity to grow and move beyond their means. Thus stress within the zone of resistance and adaptation is essential for the natural course of life to run. That being said, the extent of this zone differs from person to person and across conditions and this judgment has to be an individualistic one. The problem occurs when we try to prescribe to a collective idea of the ideal level of stress an individual must bear instead of identifying it as the personal capacity that it is.
Carl Jung, one of the greatest minds in psychology, speaks about a principle called 'enantiodromia'. Initially explained by Heraclitus, it refers to the tendency of things to change into their opposites. According to Jung, the superabundance of any force inevitably produces its opposite. Essentially, it means that an excess of something considered to be 'good' may very possibly lead to something 'bad'. And the 'bad' too is required in some amounts to create something 'good' (for example, the intestines host a range of bacteria which in the right amount are indispensible to our survival).
So it becomes important to acknowledge that over ambition, and a never-ending need to succeed while may be seen as positive signs of growth in the initial phases of one's life, an unrelenting effort towards the same can cause the very opposite of the effect one set out to create. Working to the point of negligence of every other priority in life and prioritizing relationships to the disregard of professional pursuits are both extreme forces that not only place extremely challenging demands on the physical and mental resources, but also lead to one's own downfall in that very regard which was prioritized.
Thus the key lies in finding and maintaining one's own point of physical and mental equilibrium and understanding how one relates to another. Balance does not strike in one day but takes deliberate tweaking over time where one begins to understand the subtle changes which are required to create just the right amount of stress which moves the person in the required direction without putting at stake the all-important point of equilibrium.