This is from another Quora response which has gotten more than 500
upvotes thus far. The original question was “What is the dark side of meditation that gurus won’t talk about?”
A: I don't know about gurus, but I think the sheer power of meditation goes very understated.
If your practice is sincere, disciplined and regular (daily) and if your Soul decides you're ready, meditation may deliver you into the throes of a full-blown Awakening. If this happens, expect almost everything you ever believed to be "real" to be exposed as a lie. This includes your basic understanding of who and what you are.
This is on one hand the most liberating thing that can possibly happen to you! All those things you thought were worth torturing yourself over are suddenly meaningless, and you're free! There is boundless joy, great love for all creation, ridiculous levels of bliss and beauty and unity.
But… then the ego senses its imminent end, and it fights back. That's when the hard work starts. You'll stare into the mirror and not recognize yourself or know exactly how you got there. Your name/career/lifestyle/partner may not “fit” anymore. You'll see all the toxicity and dysfunction in close relationships and have to struggle with how to handle them. Friends will sense your new energy and feel threatened by it because it touches on their own lies. Some start to drift away and loneliness shows up. The ego will whisper to you that it's not worth it.
You go to war with yourself. Who did you think you were, anyway, waking up like that?
You will wonder if you're going crazy. There will be dark nights of the Soul. You may feel like an alien in your own body and in a sense you are—you as an egoic individual are being purified, replaced by and unified with Divine Essence.
If you do find yourself in Awakening, it’s good advice to seek support from a spiritual advisor (a local yoga studio or healing center may be able to refer you, if needed). This is very difficult work to do alone, and although you can resist by not participating in it, the Awakening itself cannot be undone.
Don't let any of that scare you away from meditation, though. Awakening is a beautiful, sacred transformation, and unless you deliberately induce it with some esoteric breathing practices or other methods, it usually won't come for you until you're ready. But when it comes, it will be unmistakable, so strap in; it's a wild ride, and not for the faint of heart.