Satan loves to torment people with negative thinking about themselves. "I can't do that", or "I am a terrible person", or "I'll never amount to anything", etc. are often thoughts of the Christian and non-Christian alike. For the believer, they are not our own thoughts, but plants of impressions that when we receive them, often they are felt as if they are our own thoughts, and immediately they are uttered through the mouth, which seals the deal for the devil---because he doesn't know what we are thinking until we say it. What we speak becomes our reality. It takes a strong work of the Holy Spirit to bring us to correction about the negative talk we utter and the power of words, and to free us of such bondage of self-degradation.
For the unbeliever, it further mires them into the darkness they are living in, and they need the light of Jesus Christ to open their eyes about who they are to Him---LOVED!
We are King's kids! Royalty! We need to train our minds and tongues to reflect that truth. When we fully believe it, our lives will change and the devil's taunting will become useless...and eventually cease.