Prize to the first person who tries to explain in seriousness why one of the below things has to be so.
  1. People only puke a mouthful of puke
    This isn't a technical problem at this point. Pixar could create some digital puke CGI. Is it because moviegoers get grossed out by copious amounts of barf?
  2. Everyone has an iPhone/MacBook Pro
    Aren't Blackberry or Microsoft doing product placement?
  3. No one ever needs to take a dump
    Unless it's part of the plot/gag
  4. When there a bunch of people having a conversation, people speak in turn so you can hear everyone
  5. Everyone's hair is always amazing
  6. Family members coming home from all over the country for Christmas all arrive at the exact same time
  7. No one's computer crashes or freezes up
  8. Military computers type green text on a black screen one character at a time (with a type-y sound effect) like a dumb terminal from 1983
  9. Babies and toddlers often disappear for hours with no indication of who is watching over them
    And no one has baby monitors
  10. A good guy is encircled by bad guys with machine guns who open fire but no bad guy hits another bad guy opposite him in the circle
  11. Oral sex on women
    I can think of lots of implied/simulated blowjobs but rarely do characters go down on women
  12. Everyone's house/apartment is very well-decorated
  13. Every teenager's bedroom walls are completely covered with stuff, posters, etc
  14. There's *always* celery sticking out of the top of a paper grocery bag
    Was this started by the Celery Growers Association?
  15. No one has acne
  16. No one ever needs to stop and get gas
  17. No burps or farts, even among friends/relatives/roomies
  18. The baby's diaper never has a blowout/A baby never spits up
  19. House cats never barf on stuff
  20. Everyone has attractive pajamas
    I wear hole-y t-shirts and boxers as pajamas
  21. Pretty much every American gets their tampons and dog food at Wal-Mart in real life. But in the movies, everyone shops at some adorbs local market
  22. No one in the movies is addicted to lip balm
    Like we all actually are
  23. People who barely know each other agree to go on a date then part without exchanging information
    Suggested by @tombatten
  24. No one ever has to clean up after sex.
    Seriously, how do they just roll over and go on as if no one is leaking bodily fluids all over the sheets?
    Suggested by @ashley
  25. Everyone orders a "beer" with no further specification
    Suggested by @Hyner
  26. Everyone ends their phone calls abruptly. No goodbye pleasantries.
    Suggested by @sandydanto
  27. Women don't carry a purse or a bag yet have everything they need like a wallet, phone, keys, and lip balm (although this last one might not be something movie characters would carry according to your earlier post)
    This is especially true in bars and nightclubs.
    Suggested by @jentin
  28. Gifts come wrapped in boxes but to open you just need to remove the top rather than ripping the wrapping paper
    Suggested by @EricW
  29. Kudos on the sex thing. Movies don't prepare you for irl sex at all. I always thought about the scene in Unfaithful where Olivier Martinez has unprotected sex with Diane Lane in the public restroom and then she saunters back out in her little dress to continue lunch with her girlfriends like nothing happened. IMPOSSIBLE.
    Suggested by @joannaspicer