When you get high on something - including "spiritual bliss" - there is always going to be a low. The comedown is your body / mind returning to balance, or the closest thing to balance that it knows. If you desperately crave bliss while your body / mind needs balance, you are bound to label the changeover as "feeling bad," when in fact it's the best thing that can happen.Zen practice is not about getting high on anything and in so doing, getting high on absolutely everything. We then find that everything we encounter - bliss and nonbliss - possesses a tremendous depth and beauty that we usually miss.
Brad Warner, Sex, Sin, and Zen: A Buddhist  Exploration of Sex from Celibacy to Polyamory and Everything In Between
balance, bliss, expectations