Why do some Muslims feel at psychological ease concerning actions that contradict the Qur’an and Sunnah?

One who deviates from the Qur'an and Sunnah does not feel tranquility. If he persists in deviation, the light of his heart will be extinguished, and he will fall into Allah's cunning. The Prophet (peace be upon him) clarified that an accumulation of sins turns its perpetrator into one of the heedless, those who follow their whims. Sin after sin continues until the heart becomes blind and dies. Following whims extinguishes the light of the intellect and blinds the insight of the heart.