In the Star Trek TNG episode "The Chase," Capt. Picard's old archeology professor tries to enlist him in a glorious quest, decoding a message hidden in the genetic structures of humans, Klingons, Cardassians and Romulans. At the climax, a recording of an individual of the very first intelligent species in our galaxy appears. She explains that her race searched in vain for another species with which to interrelate. Lamenting their aloneness, they devoted themselves to seeding barren worlds with genetic precursors, spreading future life throughout the galaxy where none existed before. What does it mean if homo sapiens just happens to be that first intelligent race, that no other intelligent species exists in the entire Milky Way galaxy and it is up to us to provide the future of intelligent life? That's assuming that the human race can be considered intelligent, the issue is still in doubt.

In the two-part TNG episode "Chain of Command," Capt. Picard is captured by the Cardassians. An interrogator asks him how many lights there are up on the wall (four). The Cardassian mercilessly tortures Picard, trying to get him to say that there are five lights on the wall. The Captain resolutely resists until the Federation manages to force his release. As he's leaving, Picard yells one last time "I see four lights!" Back aboard the Enterprise, he confesses to Troi that he was willing to say anything to stop the torture. But what if the Cardassians had secretly transported a fifth light onto the wall just before Picard's departure? What would Picard have said? Nothing? "I see three lights"?

In the Star Trek movie "The Voyage Home," Dr. McCoy and Montgomery Scott are negotiating with Mr. Nichols, the owner of a plastics company in San Francisco in 1986. When McCoy chides Scotty for tampering with the time line by revealing the secret of manufacturing transparent aluminum, Scott responds that they don't know for sure whether or not Nichols invented it himself (highly improbable). But what if Scott had said "Och laddie, did ya not catch the man's name?" McCoy would mutter the man's name, ponder a moment, then snap his fingers. "Nichols! He was famous for achieving a breakthrough in metallurgy." To which Scotty would respond "But of course it won't do him any good. His great grandchildren however . . .

In the Star Trek movie "Generations," Kirk is trapped in the Nexus. He realizes he has the opportunity to propose to a woman named Antonia that he didn't propose to previously. Kirk is determined to do the right thing this time. This female character should have been named Ruth from the original Star Trek episode "Shore Leave." Ruth's only line of dialog, "Jim dahling," is said in a very sultry Southern drawl. This would've been yet another example of Star Trek's renown for self-reflexive re-introduction of previous characters, settings and subjects. One episode of Enterprise incorporated the Mirror Mirror universe, the Tholians and a Gorn into the plot.