How can one fear God when not feeling the severity of His punishment, and is this feeling considered disbelief?

Fear of God and hope for His mercy are both obligatory. A servant should neither feel secure from God's plan nor despair of His mercy, for God is severe in punishment and Forgiving, Merciful. One must fear God's might and punishment, for He is capable of taking hold of what the servant has committed. God has praised the prophets and the righteous for their longing (for Him) and their awe (of Him). The believer sees his sins as grave and fears non-acceptance, while the immoral person sees his sins as trivial. It is necessary to combine fear and hope; thus, he who obeys fears non-acceptance, and he who disobeys hopes for forgiveness. Among the signs of happiness is that you obey and fear non-acceptance, and among the signs of wretchedness is that you disobey and hope to be saved. To attain the fear of God, one must read the texts that speak of encouragement and intimidation, the horrors of the Hereafter, and the harms of sins.