What most significant element makes a movie bad?

all the identified points. A common one today is over-emphasis on computer-generated effects or gratuitous violence & (eye candy) little else. Why Avatar didn't win best Picture, a pedestrian (anti-technology too, all have pro/con) plot.

And poor acting!

Poor screenwriting. With poor screenwriting there won't be any cleverness to make the movie interesting and the character dialogue will seem unrealistic or inappropriate and make the movie unwatchable.

Combination of all of the above. The most annoying thing in a movie is over doing the special effects.

Thats why the John Carter BOOMED at the movies. The Beginning was not that great to me.

Nothig worse has anyone seen toothfairy 2 starring Larry the cable guy I think he was OK but Dwayne Johnson should have been in it since he was in the first one:-)

I hate that in movies, were it's so obvious that it's fake, at least put effort?

All of them can destroy a film. Not so much special effects, but a film needs to follow certain guidelines to be considered good. Good plot to begin wiiht which remains constant throughout. Good character development can be crucial if its going to be relatable to the audience. The acting has got to be believable and heart wrenching. A new interesting twist to the ending is always a nice surprise (but be careful not to ruin the plot). And finally the ending is the most important part of a film. Wether, a twist, cliffhanger, open or closed ending (leading onto another film or not) it doesn't matter! The ending is the bit the audience dread as the film is over. So you want to give a metaphorical 'BOOM' to it. The ending is what the audience remembers the clearest, that is why it must be amazing. However big action scenes are beginning to decline, subtlety is becoming more enjoyable.

poor writing and poor acting..most of the time if writing is bad the acting will be bad.

All of these can make a movie terrible!

Potential is what usually does a movie in for me. If a film has the potential to be great and turns out lackluster, that's a pretty big disappointment for me. Such was the case with John Carter and Dark Shadows.

I hate that! The Devil Inside and Dear John had horrible endings :/

all of the above, and sometimes a movie is just too long.

or sometimes it feels really long because it moves too slow?

oh yeah

Plot is essential

Poor Character & Plot Development at the expense of over the top Special Effects for the sake of special effects alone!

First of all, plot, acting, character development, music, edit, sounds, special effects, as well your company, theatre, all count to the success of a movie for YOU.

Blow-em-ups and car chases. How many do you have to see before the yawn sets in? LOL

All of the above.

long and drawn out

i hate CGI

Worked in Hollywood as a screen writer for years - the number one rule was - never kill the dog!!!! Everyone will hate the movie if they kill the dog! Remeber Independence Day! They saved the dog!

But I liked Cujo.

I am legend. Ring any bells?

Yes, It sucked! Also on the Hollywood money train it was just a wreck.

I am legend wasn't that bad. Sometimes killing off a animal can cause the audience to be heart broken and they can find comfort from the main characters other actions.

I know what you mean but this movie ended up hitting a nerve. I was still a screenwriter at this point and everyone was up in arms about killing that dog. The actual dog was eventually adopted by Will Smith. There is a good ending but nobody was aware of it.

I do still understand where you are coming from, however. Killing the dog always seems to send a film spiralling out of control. And i myself work in films. At the moment I'm just a lowly camera assistant/technician. But i really enjoy it and hope one day i get the opportunity to create feature length films.

I watched the movie "Red" centered around the senseless murder of a beloved dog, I did not think I would be able to tolerate it, but it winds up to be a decent movie. HOWEVER, I can certainly agree you should not kill the dog or your movie shall be dead in the water.

I worked on Blown Away - Irish terrorist - Tommy Lee Jones comes to American to make things right with Jeff Bridges that put him away. Had a terrific ending when they blew up the boat but everyone hated it because they killed Jeff Bridges dog. Didn't do good until later when it got rated the best explosion ever in a movie.

This is the primary reason to get up and walk out before the film is finished.

A lot of those are good reasons to not like a movie. What I don't like about a good movie is when they throw in a 5 minute sex scene "just for the heck of it".
Take a look at the great movies and you'll not find that.

Yes, some flicks are too graphic in the love scene (often put in to get a PG or R rating for better sales).

Its just plain stupid.

An open end.

A good mix of all, but I went to see Snow White and the Huntsman and Kristen Stewarts terrible acting made the movie a load of crap!!!

Bad plot and predictable story.