If you have fooled somebody in a hurtful, harmful way, don't fool yourself in return. Pretending as if it was all the person's fault for being naive and foolish, is only a way of you avoiding responsibility for your own destructive and foolish behaviors.
What about if you feel like someone has fooled you? How do you overcome the anger, feeling of betrayal, and hurt? Be willing to own up the fool inside you. Accept the fact that you were naive. Be compassionate with yourself for any hurt you sustained. Then resolve to be less foolish next time around.
Keep your heart open to others, but let your head guide you as well.
(photo copied from another website)