Are they meaningful to you as a viewer? IMDb has their standard list of genres that I find mostly accurate. I still believe Terminator should be classified as a horror film, but it's otherwise mostly accurate. The main list of movie genres I support here are:
Action, Adventure, Animation, Biography, Comedy, Crime, Documentary, Drama, Family-Friendly, Fantasy, Giallo, History, Horror, Mockumentary, Music, Musical, Mystery, Noir, Romance, Sci-Fi, Sport, Thriller, War, Western
I think I'll need to add 'Found Footage', 'Superhero'. What other genres are acceptable? Where does one draw the line at what is considered a primary genre and a subgenre?
Documentaries and Mockumentaries. A mock shouldn't be an extension of a doc because a mock is meant to entertain while a doc is meant to be truthful, so it ought to be a primary genre. Not necessarily funny to be lumped under comedy, and not necessarily any main genre type really. More of a style, like 'Noir'.
Giallo is a blend of crime and mystery, but is it always both? Does it make sense to consider it a primary genre as compared to a subgenre of crime and/or mystery?
Then there's all sorts of subgenres, especially regarding exploitation genres.
How many can you list?