Sefer Yetzirah the foundational book of Kabbalah teaches: Man’s greatest desire is pleasure and man’s greatest fear is pain! Now, the irony of reality is, though pain of course is no good, pleasure also is not good! because as we see from drug addicts or even people who go into spiritual nirvana, monks etc. they lose touch with reality and their lives basically become a soulless body, so the truth of the matter is, the way God structured our reality, as we see clearly in Judaism, that we always go up and down; go into pleasure and into reality!