As tempting as it is to go with out gut reaction when watching a film, it's hard to truly know how good it actually is without a bit of time. It takes numerous rewatches and distance from the hype of release to truly get a measured view on a movie and quite often your opinions will change. Just look at Avatar. At the end of 2009 it was hard not get swept up in the hype surrounding James Cameron's sci-fi epic. A few years on, it may still be the biggest film of all time (unadjusted for inflation - those 3D glasses added a lot), but outside of that bubble of release it's hard to muster the same enthusiasm for what is a good-looking retelling of a well-worn story.
Then you have the opposite cult films that take decades to be fully appreciated. 1982 saw the release of both The Thing and Blade Runner. Now viewed as masterpieces of the sci-fi genre, at the time they both failed to connect with either audiences or critics, neither making their money back. With the aid of home video, over the years people got a chance to reevaluate these bleak pictures and appreciate what John Carpenter and Ridley Scott had crafted.
It's more common than you might expect - audiences weren't sure what to think of Citizen Kane at first. So you really can't take what the initial reaction was as a measure of the film's actual long-term reputation. Unless its Green Lantern. No one will ever go looking for merit in that.
It's not always an obvious source (friends, critics, boredom) that leads you to reevaluate a movie either; sometimes its actually another film that changes its reputation.
Here are ten of those influential films that (sometimes unfairly) changed how we think about classic movies.