|Out of universe information|
Joe was unable to create or tell amusing jokes or stories of his own, but began to tell of the visions of SG-1 he sees as if they were stories he had conjured out of thin air. To start with, he told these visions to his son Andy Spencer and the customers in his barbershop, entertaining them where he had previously been nothing but a bore. Later, at the suggestion of his wife Charlene Spencer, he started to write them down and send them in to various magazines (all of which reject them) instead of telling each and every individual the tiniest of details relating to SG-1. He also knew about Brigadier General Jack O'Neill's feelings toward Lt. Colonel Samantha Carter, which he promised not to tell anyone.
Eventually, people grew tired of his tales of SG-1 and they stopped coming to his barbershop. Despite his wife's urging, telling him to stop writing the stories down, he continued to type and becomes convinced that the visions are actually happening. After years of too-intense focus on SG-1, long since passed into obsession, his wife left with their son. At that point, he tried to find evidence that what he was seeing is real, collecting data on mysterious stellar phenomenon and unexplained deaths, but was unable to contact O'Neill.
In 2005, he tracked down where O'Neill lives and confronted him with a toy gun at his house in Colorado Springs. Stargate Command discovered that the reason that he had been seeing the visions, flashes of the life of O'Neill, was because of an Ancient long-range communication stone brought back from P3R-233, the same world as the Quantum Mirror. The device, which was activated by O'Neill when he touched a mysterious black stone in Dr. Daniel Jackson's lab in 1998, connects two minds together telepathically and Joe, who possessed the same Ancient Technology Activation gene as O'Neill, activated the companion device when he touched the stone at the garage sale. He took O'Neill to see his wife who wanted to divorce him and O'Neill revealed the truth to her, presumably saving his marriage. (SG1: "There But for the Grace of God", "Citizen Joe")