It seems to be a law of nature, or at least of human nature, that a certain level of discomfort is essential to our comfort. We go to great lengths to keep our sense of discomfort at the proper level (somewhat like setting a thermostat), and that level seems to be set innately at a different place for different people. Just as we can maintain the temperature of our homes regardless of the weather that rages or languidly warms us outside, so we engineer the comfort level of our souls to a set degree regardless of the ease or difficulty of our circumstances.
I have noticed in my own life, for example, that I maintain set levels of discomfort where finances and sport are concerned. Over the course of my adulthood, my income has gradually increased and with it, my standard of living. Nevertheless, I continue to increase my expenditures proportionately such that my overall sense of how well I'm doing at covering my expenses is roughly the same; I keep up with it all in the same manner regardless of the amount.
Similarly, I have always gone running on a regular basis, and yet my penchant to do so has evolved from an occasionally habitual streak of running (with the vague notion that if I failed to do it in my youth, I would never do it), to regimented training arcs that correspond to well-defined goals. The difficulty with which I used to complete a two mile jaunt around the block and with which I completed my last 20-miler for marathon training today is, however, roughly the same. I marshal all of my efforts until the goal is achieved and then the next goal must be more difficult so that I can maintain the same sense of satisfaction in accomplishing it.
Examples of this phenomenon abound. Recent research into the science of weight loss has yielded up the theory that the body maintains a set level of body fat through various physiological mechanisms which seek to maintain the status quo. (http://www.academia.edu/497061/The_Concept_of_a_Body_Fat_SetPoint). Even when people carry an unhealthy amount of weight, their bodies seek to maintain that set level of fat. A similar phenomenon occurs in the brains of drug addicts, whose minds reinforce addictive behavior.
When we feel discomfort, we so often point to the circumstances of our lives when really, they are just the materials with which our souls reinforce their habituated state. So much could fail, so many of the materials that, by remarkable chance, populate our lives, could fall away and we would still preserve roughly the same outlook, the same level of comfort and discomfort.