How I learned to stop worrying (about what other people think) and love the movie
It takes a LONG time for you to develop an opinion that is truly and wholly your own. When you're at your youngest, your opinions are influenced heavily by your parents and the environment in which they raise you. As you develop socially, your opinions can shift to appeal more to the friends and circles in which you travel. I saw Scary Movie 4 times in the theater, because that's what all my friends were going to see. As I started traveling in more "alternative" social groups (cough cough, freaks and geeks, cough) I would try to convince others (and myself) that there was no better film on this earth than A Clockwork Orange and independent cinema was the be-all-end-all of quality film making (we'll call this my "snob" period).
I really have to thank my husband for the point I've gotten to now: I refuse to like or dislike something just because someone else says it is or isn't any good. I also refuse to curb my opinions based on how others are going to react to my opinion. I think the freedom to do this comes from  maturity (read: age) and  knowing and trusting the people who really matter to you will not think less of you if you disagree with them about whether the Star Wars movies are great or not (they aren't, deal with it, that's right I SAID IT). You don't like that Hall & Oates is blaring out of my car stereo right after a Tool song, immediately followed by Cat Stevens? Roll up your windows, because I'm having a sing-along.
When it comes to movies, the biggest criteria I have for whether I liked it or not is Did I enjoy the experience of watching this movie? This criteria causes me to DISlike a lot of "good" movies (ie, the Wrestler). A movie might be well-written, well-acted, and well-directed, but if at the end of watching it I feel like I should toss myself out of a window, I'm sorry, but, no, I didn't like it. This is not to say I can't like sad movies, but they need to compensate for that sadness by being especially thoughtful or compelling (Schindler's List, American Beauty). If the entire movie is about crappy people doing crappy things to each other and learning nothing from it (Closer), then I'm going to regret the hours I spent watching it.
My FAVORITE movies are the movies that make me want to watch them over and over again. They might be provocative (Children of Men); they might be uplifting and fun to watch (John Water's Hairspray); they might be movies I identify with personally (16 Candles); they might be so awful or quirky/strange that they defy description ( Earth Girls Are Easy).
Wait... what's that I just said? Some of my favorite movies are bad movies? Yes, yes indeed. There is a special place in my heart reserved for movies that have reached the point of awful, realized it, and embraced it. Crank, for example, has a premise so preposterous that they knew plausibility was never within their grasp, and they EMBRACED that fact and made one of the most absurdly entertaining movies I've seen recently.
With all that said, sadly, the film industry today doesn't make a lot of movies that meet the above criteria. This is how my husband and I acquired the nicknames "the Statler and Waldorf of Facebook"; we trash most of the movies we see for the awfulness that they are. Do you want to know a secret? I get almost as much pleasure from picking apart and ranting about a horrible movie as I do from seeing a genuinely worthwhile one. THIS is the secret to truly enjoying the movie-making experience: find a way to enjoy something that might otherwise make you question leaving the house to go see movies at all anymore.