It's like most things to start with it's got to be the type of film or series you might enjoy.
I wouldn't watch horror, war, musicals, westerns not my sort of thing at all.
Then it's the quality of the acting, period drama is something I would watch BUT if the acting is terrible I wouldn't continue watching the series.
I am watching a re run of Downton at the moment and I enjoy it, would like to see the film.
Like most things it doesn't appeal to everyone.
We have such a good choice of drama series on the TV now we are spoilt for choice.