WHAT MAKES A GOOD MOVIE?

This isn't really something with a simple answer. It really depends on what kind of movie I'm watching.

Drama: I want good writing and dialog. I want believable characters with really good actors playing them. I want to feel the story as if it's happening in the real world and I want to leave the movie feeling good about the outcome.

Action: Well, obviously, I want action. I want believable action stars, but they don't have to be the best actors. The writing should be good, decent dialog, but the plot doesn't necessarily have to blow me away. I want lots of entertaining action, be it fights, chases, whatever. I want my heroes to win the day.

Comedy: Obviously, I want to laugh. Whether it's funny jokes, witty dialog, or physical comedy, I want to split my sides laughing. Plots can be anything from the absurd to the downright stupid. But, as long as I laughed, it's a good film. I want good, funny writing, believable actors who can tell a joke, and I want to leave the movie feeling good, like I just had a visit from a good friend.

Science Fiction: I want a good plot, heavy on the science and the fiction. IE: this technology exists, this is more or less how, but it's nothing we have now. Plots have to be good, I want good characters played by competent actors, but not necessarily the best actors. And, I want special effects, lots and lots of special effects. Makeup, weapons, explosions, ships and whatnot. Effects are important. Costumes and sets are also important. I want to feel like I'm in the movie's world.

Fantasy: Fantasy can range for me. It's not my favorite genre. I want magic and a good story. It doesn't have to be the best plot, but I don't want anything absurdly stupid. I know that's kind of vague. And, like Sci-Fi, I want special effects. Magic, creatures, whatever. I want lots of effects.

Horror: Also not my favorite, but I do enjoy some of the classic horror films, especially the creature features. Plots don't have to be the best, but I want lots of monsters and fights. Drama can help, makeup is a must. Competent acting is also essential to sell a good horror, but not as necessarily in some of the monster movies, such as Godzilla films. (Godzilla films are almost in their own genre for me)

I know there are more genres, but that covers most of what I watch. I watch a lot of films that cover more than one genre. Above all, as TJ said, a movie has to entertain me to be good. What entertains me? Lots of things, depends on what I'm in the mood for. See above for ideas. My number one sin as far as movies go is boredom. If it bores me, I won't finish it. Period.