W.W. Jacobs's story illustrates the adage "Be careful what you wish for." Sometimes this observation is expressed as "Be careful what you wish for, lest it come true." The three wishes that the Whites request do come true; unfortunately, these wishes have not been made carefully enough, despite the warnings of Sergeant Major Morris, who has told them that the last man who owned the monkey's paw made his third wish for death.
After the old soldier who sells the monkey's paw to Mr. White departs, the Whites ignore even the final warning of the Sergeant Major to throw away the talisman, believing that he is just superstitious. They do not think through their wishes to the possible consequences because they let their immediate desires dictate what they ask the monkey's paw to give them.
The first wish that Mr. White wishes for is suggested to him by his son Herbert, who takes a a rather cavalier attitude toward the talisman. For, when Mr. White tells his family that the soldier told him to toss the paw in the fire, Herbert says in mock horror,
"Likely...Why, we're going to be rich, and famous and happy. Wish to be an emperor. Father, to begin with: then you can't be bossed around."
When Mr. White expresses doubt about what to wish for, Herbert observes that his father would like to be clear of the mortgage on their house. "Well, wish for two hundred pounds, then that'll just do it."
What Mr. White and Herbert forget to consider is from where this two hundred pounds will come. That is the tragic mistake that they make; for, two hundred pounds is the accidental death insurance payment on Herbert White. Needless to say, Mr. and Mrs. White are devastated over the death of their beloved son; now they are alone in their isolated location, and their days "were long to weariness."
Then, again the Whites do not think through their second wish because in her loneliness and grief, Mrs. White coerces her husband to wish for their dead son to return to life. "I wish my son alive again." But, the horrible consequences have not been thought of: Herbert was in a terrible accident. He returns to life, but he is a monstrous deformity. The Whites have no choice but to use their third wish to be as it was for the last person who owned the monkey's paw: death.