The website Movie Mistakes has collected over 100,000 mistakes spotted in movies by fans. Now they've released their list of the top mistakes of 2013, as voted by the site's users. Some of them are factual errors, like a scene in The Hangover III:
Chow is carrying around $21 million in gold bullion. A bar weighs 400 ounces. Gold prices at that time were around $1,200 per ounce, and he's got two bags, therefore he's supposedly carrying 8,750 ounces, or about 550lb, on each arm.
While others are mistakes in continuity, which is just weird things that happen in the confusion of filmmaking that someone should have caught, like what happened in The Hunger Games: Catching Fire:
The number of arrows that Katniss has in her quiver goes up and down through the games. For example, In the second cornucopia scene when the career tributes from Districts 1 and 2 attack Katniss, Peeta, Wiress, Johanna, Finnick and Beetee, one shot shows three arrows left, but there were plenty used during the rest of the film.
Go see all 30 of these trivial mistakes from the movies of 2013, which probably won't spoil the fun of watching these movies again, but will cause you to look closer next time. -Thanks, Jon Sandys!