I disagree. The trailer looked good and the film delivered the promises of the trailer. It was truly an amazing film with funny but dark humor and tragic humans fates. It's kind of a roller coaster ride from start to finish.
When a shooting star streaks through turning blackness into day, make a wish, think of me.
-RW-
It's the kind of movie people either love or hate. You don't love it. No biggie.
But what this means is, you can only handle content like the one Filth contains in small doses. The trailer is basically an extremely short version of the movie. In small doses, the craziness and darkness look stylish and fun but when extended to show the full story behind all that craziness and darkness, some people find themselves turned off. Kind of like how seeing other people doing charity work in third world countries seem fun and enriching when you see it from afar but when you actually sign up for it and get down to it yourself, you'll find that there's a lot more to it than what you can maybe handle and realize how utterly naive you've been to have thought it was all sunshine and roses, with only the occasional rainfall when in truth, it rains more often than it doesn't. Still, some people learn to love the rain and thusly become enriched, while others can't handle the suffering and go home.
So, might I suggest you give it a bit of time and then try watching it once more? A second watch sometimes bring about an entirely different experience. I know some people who hated it at first watch but loved it from the second one on. While I didn't hate it right off the bat, it did make me go WTF. Watched it again a couple of weeks later and found it to be rather interesting and by the third, it's on my list of DVDs to own. ;o)