Fear can be an exceptional motivator, possibly more effective than love in motivating someone to faithfully follow rules, to always keep a routine, to never question authority, etc.
And fear can also be an exceptional motivator in getting someone to do something they would NOT otherwise do.
It may be more powerful than love in overriding logic in this way, that the person doesn't even question why they're overriding their logic to do something illogical, as if there's not even a possibility of there being an alternative.
Fear and denial may be closely related.
In summary:
Fear can keep someone completely submissive and in check & predictable.
OR
Fear can cause someone to become not submissive and not in check &
to be completely unpredictable.
It can move someone to be completely controlled by someone
OR
to be controlled by no one.
Slavery
OR
Chaos
