I think that the biggest cult characteristic is their use of Mind Control. One aspect of mind control is the use of emotional control.
Read the following quotes from Steven Hassan, a former member of the Unification Church, and see if you notice any similarities:
"Guilt and fear are necessary tools to keep poeple under control. Guilt is probably the single most important emotional lever for producing conformity and compliance."
"However, most cult members can't see that guilt and fear are being used to control them. They are conditioned to always blame themselves, so that they respond gratefully whenever a leader points out one of their 'shortcomings' ."
- Combatting Cult Mind Control, pg. 63