A person without bitachon leads a stressful life of “pizzur hanefesh” – “Having a scattered soul.”
Sometimes the pressure of life makes him do unpleasant things. Lying, cheating, and stealing might not be natural for a Jew, but pressures and worries may sometime lead a person there.
Even when dealing honestly, a person without bitachon may have to go to great lengths or travel far to earn a living, putting his physical and spiritual life in danger.
He always worries. Maybe he didn’t flatter or honor the right person? Maybe that person doesn’t like me?
Also, since he relies on others, he has to always worry about the people that the people he relies on rely on! It’s a horrible chain of worry as he never knows what will happen. He worries about the markets, he worries about disasters, he worries about politics!
All this fear, worry, and stress are outcomes of a lack of bitachon.