forboding movie previews

Most weekends I watch a couple of movies.  Lately, it has mostly been movies I am fairly sure that I will at least find tolerable, but every once in a while I take a chance on a movie that there is a good chance that I will not like.  Nothing makes me more leery of these movies than watching preview after preview at the beginning of the DVD of other movies that I have absolutely no interest in.  "Maybe I misjudged what type of movie this was going to be," I wonder to myself.  "I'm not really in the mood for an artsy/dramatic/ultra-low-budget/emotional/understated drama."

Usually my reticence is proven unwarranted, as I do end up finding some enjoyment in the movie.  Even so, there are times when I get a few scenes in, decide that my initial fears were spot-on, stop the movie, and move on to something else.

The previews that make me concerned usually fall into one of the following categories.

• The previews that show that every character in the movie has a horrible life and there is no indication things are going to change.  These previews are usually edited to be extremely gritty.  They make me wonder if the movie I picked out for the night will leave me in a state of nihilistic depression.
• The previews for corny family comedies.  I start to think, "Wait, am I going to laugh at any of the jokes in this movie?"
• The previews for artsy European movies with poor protagonists on a journey to find themselves or just surviving in a stifling culture.  The film is always a bit grainy and usually makes note of all the film festival awards it got.  This immediately makes me wonder how drawn-out the storyline of the movie I am about to watch is going to be, and whether there will be a real conclusion to the movie.
• The previews for other movies I have already seen and did not like.
• The previews for foreign films in general.  If all of the previews are foreign films I suspect that the film makers for the movie I am about to watch were not overly concerned with the interests of the American movie watcher.
• The previews for mid-nineteenth century period pieces.  Almost no movies I like take place in the nineteenth century, as it is dominated by romances and spaghetti westerns.  The ones I do like that take place in that time period almost always bring something different to the table (Should I be embarrassed that I'm thinking of Cowboys and Aliens as a good film placed in the nineteenth century?  At least I was not thinking of Wild, Wild West.).
• The previews for teen movies.  There are teen movies I like, but it makes me nervous if the people picking previews for this movie only selected other teen movies for the previews.
• The previews for revenge movies.  I'm not very interested in movies where the central point is revenge and nothing else of value is brought to the table, so I don't want to think I'm about to see a movie like Death Wish or The Last House on the Left.

There are others as well, but that accounts for most of my red flags.

Do you have any types of movie previews that makes you wonder if you made the right choice to watch some specific film?  What are some of your red flags?