Do not feel sorry for the intellectually and developmentally disabled simply because they do not understand as you do. It is pretentious to assume your existence is superior to theirs merely because they are not as intelligent as you. There are very probably plenty of mentally handicapped men and women who live much happier and more satisfying lives than you do. And if you do not envy the man who is happier than you I believe that reveals a certain kind of intellectual disability in yourself.