What it means to be fully human is to strive to live by ideas and ideals and not to measure your life by what you've attained in terms of your desires but those small moments of integrity, compassion, rationality, even self-sacrifice.
Fantasies have to be unrealistic. Because the moment, the second that you get what you seek you don't, you can't want it anymore. In order to continue to exist, desire must have its objects perpetually absent.