A movie's fame and notoriety can be based on a number of factors beyond just the overall quality of the film or the significance of the names behind it. Controversy can play a big role in a film's success, i.e. any press is good press.
If a film contains controversial or buzzed about subject matter, it can become more well known in the public consciousness than others. This is proven throughout film history that movies with a level of controversy attached to them may stand the test of time more than their contemporaries.
Sometimes films garner controversy due to only one shocking scene. These can involve gratuitous or outrageous depictions of sex, violence, or just unbelievable grossness. These types of scenes can serve the overall shocking story, but more often than not they are simply there for the added shock factor and potential fame. The cultural impact of a particular scene can prolong a film's longevity, but can also overshadow the rest of the film around it.
