Adult Perspective and Credibilty (Situational Irony)
The unique perspective of childhood, such as the ability to correctly identify a drawing of a boa constrictor digesting an elephant, is lost with adulthood. However, it is only by attaining adulthood and growing up that a person develops credibility. Adults, who are supposed to be respected by children, are not always in possession of all the facts and the ability to see things "as they really are" is lost with adulthood. One can therefore have insight or credibility, but not both at once.
Meaning (Situational Irony)
During the little prince's travels among the various asteroids, he meets several different kinds of adults. Most of them engage in meaningless tasks, such as lighting and dimming street lamps on an asteroid where nobody lives, or counting the stars and imagining that they own them all. The adults, particularly the vain man and the king, are very self-important and convinced of the necessity and importance of their tasks, yet objectively they are not productive. The little prince's goal, which is to love and serve his "ephemeral" flower, is one deemed by the adults to be ridiculous.
Accomplishment (Situational Irony)
Having accomplished his goal, the little prince is too tired and unable to return physically to his asteroid. The only way he can do so is by allowing a poisonous snake to bite him and by leaving his body behind in the desert, returning in spirit only. He accomplished his goal by finding the knowledge he sought, but it killed him: he was unable to physically return so that he and the flower could benefit from it.
Solitude (Situational Irony)
Each of the men the little prince meets on the way to Earth is alone on his asteroid, much like the little prince was alone on his. They all have absolute power over their surroundings, and are in control of what they do since there is nobody else to contradict their will, yet it does not make them truly happy. Only by interacting with other people can the king and the vain man get what they want (power and admiration, respectively), and they can only satisfy the deepest desires of their hearts by leaving their respective domains. But they choose to remain anyway. Only the little prince chooses to leave his planet.
