Most real growth on the spiritual path comes when we allow ourselves to go beyond our comfort zones. This is because a comfort zone is mainly a "ground" that the I sense clings to and feels secure in, and by removing those "grounds", one is left with the requisite openness for wisdom and growth. A comfort zone can range from subtle and psychological to more substantive and material forms, but most real demonstrations of stepping outside of a comfort zone should include a material actualized form. The reason for this, is that for most people, a lingering comfort zone is self-deception which attributes qualities that haven't been demonstrated. Moreover, one whose inner actions also contain a practical application have a quality of confidence (and something unstatable), which strictly "mental warriors" ("i could do that") can never achieve. Many ancient and indigenous cultures understood this wisdom and had/have various rites of passage. (To the extent that modern culture has rites of passage, they are mostly vapid and serve a business and consumer model.) Nowadays, a lot of what passes as spirituality is more wellness and self improvement, whereby one is made to feel more comfortable and have a "better" attachment to the various grounds of self. Often, people with no real life stresses (in a gather food and a lion might kill me way), turn their unspent/frustrated energies into neurotic anxieties and believe what they need is comfort (via "spa" spirituality). However, what they really need is to be challenged and pushed beyond their comfort zone patterns (which are the very patterns of their neurosis). Even those who have been on a path for sometime should be vigilant to see where/when the i sense settles into patterns/grounds. It is not unusual for lofty concepts to turn into comfort grounds, nor for Tantrics to use Deities to hide behind. Even openness can become strategic. Of course, a true and balanced path should include both periods of pushing and settling (expanding and assimilating), and as one progresses, one gets a better understanding of timing. A Guru or guide are also important in helping a sadhak understand what actions are required at a given juncture. However, one can hardly go wrong by continually stepping into the depths and challenging themselves which gives rise to true humility.