We all struggle with too often or habitually doing or thinking things that we know are bad for us and/or those around us.
Our dysfunctional behavior is fueled by anger and resentment deeply rooted within us. We are angry at the fact that, somewhere along the line of our lives, our core emotional needs were not met.
Like so much anger we manifest, that which fuels our dysfunctional behavior is a reaction to fears we hold.
What we fear is that our core emotional needs cannot be met.
That enduring, fundamental human fear is two-fold: that God (or something/someone like it) is not in control of things, and that we are not lovable.
Those two fears—the one which looks to the outside world, and the other which looks to the inside—are complementary aspects of the same fear: That we and the world at large are not grounded in love.
The conditions necessary for the reality of human free will—being mainly our absolute autonomy—means that it always will, too. The cost of our ineradicable uncertainty is our free will.
(Note: While its assertion that God is love automatically renders Christianity a perfectly comprehensive answer to the one great human fear, being Christian does not inure anyone from the acute, ongoing angst of existential doubt. Every Christian remains, after all, a human—free will and all.)