Why does benzene undergon electrophilic substitution reaction easily and nucleophilic substitutions with difficulty?

Due to the presence of an electron cloud containing 6π-electron above and below the plane of the ring. benzene is a rich source of electrons. Consequently, it attracts the electrophiles (electron-deficient) reagents towards it and repels nucleophiles (electron-rich) reagents. As a result, benzene undergoes electrophilic substitution reactions easily and nucleophilic substitutions with difficulty.