Shows where the doorbell rings, or a knock at the door, and the person in the house/apt/flat/whatever goes up and immeditaely opens the door. Without looking through the peephole (which is there), or asking "who is it?" first.
Federation starships have minimal restraint systems (basic seatbelts or "lap bars") for the bridge crew, while NO ONE ELSE ON THE SHIP has any type of restraint system. Think about the hundreds of crew men and pasengers, getting tossed around the hallways, while the Klingons pound the Enterprise.
Sci-Fi series, where people are kidnapped/ probed/ genetically altered/ programmed to be sleeper agents, etc. Eventually, they get rescued and deprogrammed/ have their anatomy restored, and mentally seem to be the none the worse for wear. I'm looking at you, Trek...
Also, you can't alter someone's DNA with a tricorder, and they suddenly sprout wings, or turn blue, or become invisible, etc. If you alter a grown, living organism's DNA like that, they just die. They don't INSTANTLY MUTATE into some other being. And let's not talk about how you "correct" their DNA, and they instantly shape shift back into their human form.
And IF that type of technology exists in the future, THEN.... no one would ever die of old age, or disease. Aciddental deaths? Yes. But death related to aging or illness? No. Freakin'. Way. You would simply go to Sick Bay, "refresh" your DNA, and look 29 forever.
Every major alien attack on earth centers around 6 major cities... Washington DC, New York City (or it's doppleganger, such as Metropolis or Gotham City), Los Angeles, Paris, Las Vegas, or Chicago.