Recently I reread part of master-of-Chinese-culture Nan HuaiJin (南懷瑾)'s book on his dialogues with (mainly) Tibetan Buddhism meditators from USA (現代佛学者修証者對話), many "horrible" meditative episodes were reported (like a lady with the nails of her big toes blackened and later fell off!) Most of these episodes relate to different manifestations of the process of kundalini of Tibetan Buddhism (密宗拙火定). In the past, such difficulties were supposed to form part of one's spiritual training program, along the theory of "physical hardship can train up one's spiritual strength", the same theory behind some modern programs (e.g. Outdoor leadership programs of the various Outward Bound schools). Before I proceed, I must add that these "horrible" episodes can actually be partially avoided, or have its discomfort effects lessened, if one proceeds slowly and with proper guidance. But if one chooses to go this way for spiritual reasons, that will be another story, and will be quite justifiable.
Master Nan was frustrated to see that some practitioners, as documented, failed to take such opportunity to elevate their respective spirituality. Albeit they got good health as a (side) benefit, but failed to earn the spiritual benefits because they had not learned the Great Vehicle theory of Buddhism. It is interesting to note that North Sung Taoist Zhang Bodun (北宋道士张伯端) the author of Taoist Classic Wu ZhanPian (悟真篇) shared similar views (check my previous post here).
There has, however, always been people who like to take the benefits from these meditative or inner practices for reasons other than spirituality. Or actually: "spirituality for personal gratification: or finding justifications for personal gratification through spiritual reasons! What am I talking about? The most ostentatious example being the practice of sexual chi-kung face-lifted as spiritual practice. It happens today, as it happened in all history: sex is simply too fascinating a subject!
Being bred from an authoritarian social structure, Chinese culture is inundated with theories and practices for the personal enjoyment and gratifications of the wealthy class. The swallowing of pills 外丹 (made by Taoists or Fanshi（方士，literally intellectuals with magic formula) by the wealthy was considered a super-highway to spirituality. A number of Emperors in Tang Dynasty died in the process, due to heavy metal poisoning. Failure? No matter. Modern day connoisseurs of gratification in the Far East still make the lives of endangered animals (like tiger) even more endangered: they covet their most private parts!
For today's middle class (now that more are considered wealthy by past standard), a week-long (or week-end-long if time doesn't allow) meditation retreat to some scenic air-conditioned resort for couples will be lovely diversion to one's hectic urban life. Complete with meditation, spa facilities, yoga/pilates/tai-chi (always) introductory courses; together with organic food (preferably vege), nice music. Excellent way to "recharge one's battery", and for what purpose? To enable one to better equip going back to the "battle field" of modern days. "To kill" as they love to say metaphorically. A "great" way to exercise one's spirituality!