Why is everyone such a hard-ass? You can't just disconnect and enjoy a movie for what it is? You can't refrain from picking something apart for 90 minutes? Granted, there are some movies that I've turned off, got bored with, or just thought sucked, but for the most part I am easy to please when it comes to entertainment and I don't think there is anything wrong with that.
Warm Bodies, The Croods, Atlas Shrugged, Argo, Hotel Transylvania, Total Recall, House at the End of the Street, Hunger Games... just a few movies off the top of my head that I've seen recently that were all entertaining.
When watching a movie I'm not looking for something mind-blowing. I'm looking to be entertained and taken away for an hour or two. I'm suspending disbelief.
The behavior you describe is more systemic than anything. People need greater and greater feats for the wow-factor. The same thing goes for video games, music, etc..
The video games nowadays are mind-blowing to me; then I'll go online and read a dozen comments about how so-and-so is garbage and can't write a story to save their lives, or how about x video game company released complete garbage, or how the music is the same sounding fart-noises from a year ago.
The fact of the matter is that most people, in the U.S. at least, have become extremely jaded. Something which was completely amazing 5 years ago is only ho-hum today. If you took "wrath of the titans" and showed it to moviegoers 30 years ago, it would have been frigging amazing. Back when I was a child I watched claymations, which sucked in comparison to the incredible CGI-fests of today's movies, and enjoyed them, played video games where you played the same board over and over again for hours, listened to music off of a cassette tape which degraded over time and sounded like garbage in comparison to today's FLAC files and CD's, yet I still enjoyed everything immensely.
When I watch movies, I also have to turn off my super-critical analytical thinking side and just enjoy the movie, and all of a sudden things aren't so damn crappy that forum goers and critics make them out to be.
Example: The newer Conan movie. Everybody online complained about how it sucked balls compared with the original, was a garbage movie with utterly craptastic writing, etc. - you know what I actually enjoyed it. I watched it without thinking about the first movie, or the comics, and just pretended it was a new movie in it's own little universe and it was a fun watch. Every single one of my facebook friends complained about how it paled in comparison to the original Conan movie.
Same thing goes for Tron, I thought the new Tron had the best movie sound track I ever heard. I even went out and bought the soundtrack and listened to the CD by itself, but all these people complained the movie was crap. I could go on and on, but it amounts to people being so damn jaded that they just can't find enjoyment in anything anymore, and just live out their lives in a shallow existence of everything sucking, until they get that brief glimpse of happiness again when something completely new comes along, then *poof* the happiness is gone again. As if it's only a fleeting moment, something you can never truly hold on to for any length of time.