The spouse never stops griping. The children scream and fight. The dog bites the neighbor. The boss is a jerk. Sickness strikes when it's least expected.
Loved ones die.
Along comes Herb Applewhite, offering an escape from all of this. No more worry. No more unpleasantness. Surrender your life to the cult, and the cult will take care of you, handle your problems, and make your decisions for you. In Heaven's Gate, a member was free to leave, but lots of subtle pressure was undoubtedly put on anyone who chose to do so.