Teenage Mutant Ninja Turtles: Mutant Mayhem: "The Turtles sound like kids!"  Duh!  That's the point!  The *Teenage* Mutant Ninja Turtles are actually played by teenagers.  "But they don't sound like their balls have dropped yet."  Have people on the Internet only seen teenagers in movies where they're played by 25-year olds?  When this movie came out, Nicholas Cantu (Leo)  and Shamon Brown Jr. (Mikey) were 18, Micah Abbey (Donnie) was 15, and Brady Noon (Raph) was 17.  Puberty doesn't make your voice go from Emmanuel Lewis to James Earl Jones overnight.

  
Duck And Cover: "Hiding under a desk isn't going to protect you from getting vaporized by a nuke."  A common misconception about nukes is that they can turn cities into deserts and kill every living organism within their blast radius.  If you've read the manga Barefoot Gen (or saw the movie), the titular character survived getting nuked because he crouched at just the right time behind a ledge.  The author of the manga, Kenji Nakazawa, based the story on his own experience surviving the nuking of Hiroshima.  Yeah, ducking and covering won't guarantee your survival, but it has a sliver of a chance of helping.

  
Pearl Harbor (2001): "They let somebody who couldn't swim in the Navy!?"  This one got some groans from the audience and ignited a pretty long crashout from the Nostalgia Critic.  It's pretty understandable why some would think this is dumb.  People in the Navy are required to always be around water, so you'd think there'd be a requirement to know how to swim.  Yeah, that's the rule in this day and age, but during WWII?  Yeah, before the attack on Pearl Harbor, swimming was not a required skill in the Navy.  Some Naval units required it, but for the most part, it was a bonus skill.

(Hated audience reaction Trope) Things in media people complained were unrealistic that actually hold water in real life